The Development and Application of Transition Metal–Hydrides in Catalysis for Alkene Hydrosilylation and Isomerization Reactions by Alison Sy-min Chang A dissertation accepted and approved in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Chemistry Dissertation Committee: Darren W. Johnson, Chair Amanda K. Cook, Advisor Mike Pluth, Core Member Stephanie Majewski, Institutional Representative University of Oregon Winter 2024 © 2024 Alison Sy-min Chang 2 DISSERTATION ABSTRACT Alison Sy-min Chang Doctor of Philosophy in Chemistry Title: The Development and Application of Transition Metal –Hydrides in Catalysis for Alkene Hydrosilylation and Isomerization Reactions Metal-mediated alkene transformations is a rapidly developing field to obtain various organic precursors for pharmaceutical compounds, industrial chemicals, and consumer products. The pursuit of developing Earth-abundant catalysts is of great interest due to catalyst affordability in comparison to precious metal catalysts. Specifically, Ni catalysts serve as viable alternatives to previous metal catalysts due to the versatile reactivity of Ni. In addition to catalyst development, the catalyst mechanism is also just as important to inform future catalyst design. This often results in guided catalyst optimization and byproduct inhibition. The focal point of this thesis surrounds the development and investigation of Ni-catalyzed alkene hydrosilylation and alkene isomerization. Particularly, the formation of Ni–H intermediates to mediate these organic transformations. Reaction and catalyst optimization, substrate scope, and mechanism determination are reported for both alkene hydrosilylation and isomerization systems. Chapter I highlights the utility of Ni–H in these organic reactions, motivating our work described in Chapters II-VI. Chapter II reports on the reaction development and substrate scope of the homogeneous hydrosilylation (NHC)Ni (NHC = N-heterocyclic carbene) catalyst. Chapter III outlines the mechanistic investigation of the (NHC)Ni-catalyzed alkene hydrosilylation system described in Chapters II. 3 Chapter IV is a continuation of the catalytic system developed in Chapter II and III and delves more deeply to explore the electronic structure of (NHC)Ni(alkene) catalysts. Modification of the NHC ligand gives rise to trends in catalytic ability. To obtain a deeper understanding of this system, ligand steric and electronic variation are tested to observe its influence on catalyst behavior. Chapter V illustrates the incorporation of the in situ hydrosilylation system developed in Chapter II into the remote hydrosilylation of a long chain alkene. This work also includes preliminary data on an in situ generated Ni-catalyzed alkene isomerization system in combination with a hydrosilylation system to install a silicon group distal to the initial reaction site. Chapter VI outlines the development, characterization, and investigation of a heterogeneous Ni alkene isomerization system. This chapter includes catalyst substrate scope, preliminary mechanistic data, and comparison to other Ni-catalyzed alkene isomerization systems. This dissertation includes previously published and unpublished coauthored material. 4 CURRICULUM VITAE NAME OF AUTHOR: Alison Sy-min Chang GRADUATE AND UNDERGRADUATE SCHOOLS ATTENDED: University of Oregon, Eugene Rhodes College, Memphis DEGREES AWARDED: Doctor of Philosophy, Chemistry, 2024, University of Oregon Master of Science, Chemistry, 2020, University of Oregon Bachelor of Science, Chemistry, 2018, Rhodes College AREAS OF SPECIAL INTEREST: Organometallic chemistry Earth-abundant transition metal catalysis Homogeneous and Heterogeneous catalyst development Reaction mechanism elucidation PROFESSIONAL EXPERIENCE: Science Communication Seminar Chair, Alliance for Diversity in Science and Engineering, 2020-2022 Summer Academy to Inspire Learning Chemistry Summer Camp Head Organizer and Module Leader, 2022 Co-Founder, Co-President, Treasurer, Social Media Chair, Co-Workshop Chair, Alliance for Diversity in Science and Engineering, 2020-2021 Treasurer, A Community for Minorities in STEM, 2019-2022 GRANTS, AWARDS, AND HONORS: American Association for University Women Dissertation Fellowship, American Association for University Women, 2023-2024 CAS Future Leaders Award, American Chemical Society, 2023 5 Diversity, Equity, and Inclusion Chemistry Department Community Builder Award, University of Oregon, 2022 University of Oregon Women in Graduate Sciences Graduate Leadership Award, University of Oregon, 2022 NSF Graduate Research Fellow, National Science Foundation, 2020-2023 University of Oregon General University Scholarship, University of Oregon, 2020, 2021 PUBLICATIONS: Chang, A. S.; Kascoutas, M. A.; Valentine, Q. P.; How, K. I.; Thomas, R. M. Cook, A. K. Alkene Hydrosilylation using a Heterogeneous Nickel-Hydride Catalyst. Submitted 2023. Chang, A. S.; Kawamura, K. E.; Henness, H. S.; Salpino, V. M.; Greene, J. C.; Zakharov, L. N.; Cook, A. K. (NHC)Ni(0)-Catalyzed Branched-Selective Alkene Hydrosilylation with Secondary and Tertiary Silanes. ACS Catal. 2022, 12, 1102–11014. Kawamura, K. E.; Chang, A. S.; Martin, D. J.; Smith, H. M.; Morris, P. T.; Cook, A. K. Modular Ni(0)/Silane Catalytic System for the Isomerization of Alkenes. Organometallics 2022, 41, 486–496. 6 ACKNOWLEDGMENTS First off, thank you Prof. Amanda Cook for trusting me with independence from the start, for always being available to answer my myriad of questions whenever I randomly showed up to your office, for teaching me the art of organization, for supporting my outreach activities, and for always being an open ear to talk to. You have helped me grow so much as a chemist and a leader since I joined your lab in 2019. Thank you, Dr. Michael Hurst, for showing me that it’s possible to be incredibly hard-working through trying times and for your key lime pies–I will also never forget that it’s possible for a human being to completely function off 100% black coffee. Thank you, Dr. Kiana Kawamura, for being my research and outreach mentor, for always being open to having heart-felt conversations in the office, for guiding and teaching me how to traverse throughout graduate school, and for being a good friend. I appreciate all your baked goods from Sally’s baking blog and miss you and them a lot ever since you defended. Thank you, Melanie Kascoutas, for being so supportive of my every step in graduate school, for teaching me so much about passion in science and your own life journey, for providing me with so much wisdom, and for being the most considerate coworker to ever exist. Thank you to the youngest member of our lab, Allison La Salvia, for teaching me how to be calm and collected and for cracking me up in the office. Thank you to my first undergraduate, Hayden Henness, for always being a ray of sunshine whenever you stepped into lab. I appreciate everything you have contributed towards my well- being, and for being a good companion. Thank you, Victor Salpino, for showing me your drive to understand literally every single detail in reaction set up and work up and never letting go of ≤100% yield reactions. Thank you to my other undergraduate students, Lucas Thigpen, Kiera How, and Lilly Granados, for all keeping me humble and teaching me how to be a better mentor. Thank you, Cailey Carpenter, my superstar REU student in the summer of 2022. You are by far 7 one of the most hard-working undergraduate students I have had the luck to work with. You inspire me every day with each accomplishment you make in this world. Thank you to all my first-year graduate student mentees for helping me grow as a mentor and to think critically about my own research and beyond, specifically Li HaoKun, Arman Garcia, Jack Greene, and Gaby Bailey for having the greatest impact on me. Especially Gaby Bailey, who is one of my best friends in graduate school. Thank you, Gaby, for always being there for me. I am so lucky that we met during the time that we did, and that Otis was a big part of our lives then too. Thank you Khoa Le for being one of my best friends in graduate school. I have our serendipitous encounters at the UO gym during our first year to thank since we never overlapped in classes. I appreciate our Zoom lunch dates during the pandemic, our lunch dates outside the pandemic, our outings in Eugene, and your ability to be so kind and generous to everyone. Thank you to my recreational volleyball teams for keeping me grounded and active. I want to thank all my other friends who have contributed to my success and survival throughout my graduate career. I want to thank my family for always understanding my circumstances while in graduate school even if y’all may not know what I’m doing here. Thank you, mom, for taking care of me in Eugene, OR both times that I broke myself, you are amazing. Thank you Valerie for going on adventures abroad with me. Thank you, Fischer Harvel, for being my rock throughout graduate school. You are sincerely the most considerate, generous, kind, patient, and beautiful soul that I get to always laugh with and cry to. Thank you, Gene Lamanilao and Prof. William Eckenhoff, for teaching me that anything is possible to achieve and accomplish. Thank you, Andrew and Ashley at Pisces Aquaria, the owners of the local aquascaping and fish store in Eugene for opening my life to a new hobby and passion. Lastly, thank you to all the dogs in my life, especially my Appa, (Otis, Amelia, Pye, and Wesley) for showing me that happiness can be achieved >99% of the time. 8 DEDICATION To my mom. 9 TABLE OF CONTENTS Chapter Page I. CHAPTER I: The Development and Application of Transition Metal–Hyrdides in Catalysis for Alkene Hydrosilylation and Isomerization Reactions ................................................. 17 1.1 Introduction ...................................................................................................... 17 1.2 Pt–H and Ni–H in Alkene Hydrosilylation ...................................................... 20 1.3 Heterogeneous Ni Alkene Isomerization Cataylsts ......................................... 24 1.4 Conclusions and Outlook ................................................................................. 26 II. CHAPTER II: Development of a (NHC)Ni(0)-Catalyzed Alkene Hydrosilylation System using 2° and 3° Silanes ................................................................................................ 27 2.1 Introduction ...................................................................................................... 27 2.2 Results and Discussion .................................................................................... 30 2.3 Conclusions ...................................................................................................... 33 III. CHAPTER III: Mechanistic Investigation of a Homogeneous (NHC)Ni(0)-Catalyzed Alkene Hydrosilylation System ................................................................................................ 36 3.1 Introduction ...................................................................................................... 36 3.2 Results and Discussion .................................................................................... 37 3.3 Conclusions ...................................................................................................... 46 IV. CHAPTER IV: Investigations of (NHC)Ni(styrene)2 Electronic Structures and Their Relation to Alkene Hydrosilylation ............................................................................................ 47 4.1 Introduction ...................................................................................................... 47 4.2 Results and Discussion .................................................................................... 48 4.3 Conclusions ...................................................................................................... 58 10 Chapter Page V. CHAPTER V: Development of a Homogeneous (NHC)Ni(0)-Catalyzed Remote Hydrosilylation System ................................................................................................ 60 5.1 Introduction ...................................................................................................... 60 5.2 Results and Discussion .................................................................................... 62 5.3 Conclusions ...................................................................................................... 67 VI. CHAPTER VI: Development of a Heterogeneous Nickel–Hydride Catalyst for Alkene Isomerization................................................................................................................ 68 6.1 Introduction ...................................................................................................... 68 6.2 Results and Discussion .................................................................................... 71 6.3 Conclusions ...................................................................................................... 86 APPENDICES ............................................................................................................. 87 A. SUPPLEMENTARY CONTENT FOR CHAPTER II ..................................... 87 B. SUPPLEMENTARY CONTENT FOR CHAPTER III .................................... 251 C. SUPPLEMENTARY CONTENT FOR CHAPTER IV .................................... 312 D. SUPPLEMENTARY CONTENT FOR CHAPTER V ..................................... 374 E. SUPPLEMENTARY CONTENT FOR CHAPTER VI .................................... 389 REFERENCES CITED ................................................................................................ 529 11 LIST OF FIGURES Figure Page 1. Figure 1.1. Examples of M–H in industry for the following reactions: (a) Shell Higher Olefin Process, (b) polymerization of α-olefins, and (c) hydroformylation. Ph, phenyl ........ 18 2. Figure 1.2. Catalyst tuning of: (a) ligand modulation for an alkene isomerization catalyst, and (b) metal modulation for an allene hydrosilylation catalyst. Ph, phenyl; Ar, aryl; Me, methyl; Et, ethyl.............................................................................................................................. 18 3. Figure 1.3. Dupont adiponitrile process catalyzed by a homogeneous Ni–H species. Ar, aryl. ................................................................................................................................ 20 4. Figure 1.4. (a) Alkene hydrosilylation, and (b) Pt catalysts for alkene hydrosilylation. Cy, cyclohexyl .................................................................................................................... 22 5. Figure 1.5. Ni alkene hydrosilylation precatalysts with corresponding product selectivity and silane compatibility ...................................................................................................... 23 6. Figure 1.6. Development of a branched-selective (NHC)Ni-catalyzed alkene hydrosilylation system to activate 2° and 3° silanes. ............................................................................ 24 7. Figure 1.7. Exploration of the electronic structures of (NHC)Ni(alkene)2 complexes ................................................................................................................................ 25 8. Figure 1.8. Proposed heterogeneous Ni–H catalyst capable of undergoing alkene isomerization and hydrofunctionalization reactions ........................................................................... 26 9. Figure 2.1. (a) General scheme of transition metal-catalyzed hydrosilylation. (b) Base metal- catalyzed hydrosilylation catalysts. (c) Our proposed strategy to investigate the mechanism of (NHC)Ni(0) complexes to yield branched organosilicon products using 2° and 3° silanes ................................................................................................................................ 28 10. Figure 2.2. Hydrosilylation screen of 2a and 3a at 70 °C in toluene with a series of (NHC)Ni(dvtms) complexes to yield 4aa (dvtms = 1,3-divinyltetramethyldisiloxane). Conditions: styrene (2a, 0.088 mmol, 1.0 equiv), H2SiPh2 (3a, 0.088 mmol, 1.0 equiv), (NHC)Ni(dvtms) (0.0044 mmol, 5.0 mol %), and toluene (0.40 mL). Selectivity and yields are determined by GC- MS analysis using mesitylene or durene as an internal standard ................................. 31 11. Figure 2.3. Scope of alkene hydrosilylation ......................................................... 34 12. Figure 3.1. Hammett plots for 1e-catalyzed hydrosilylation of (a) electronically modified diarylsilanes (3a,b,d,e) with 2a and of (b) electronically modified vinylarenes (2a,c,e-f) with 3a. ................................................................................................................................ 39 12 13. Figure 3.2. Deuterium labeling studies. a) Expected outcomes of deuterium incorporation via Chalk-Harrod pathway for hydrosilylation, b) deuterium labeling studies with 2a and 3a-d2, and c) crossover study with 2a, 3a-d2, and 3b ................................................................... 41 14. Figure 3.3. 2H NMR monitoring of the hydrosilylation of 2a and 3a-d2 by 1e over time at 75 °C. 1H NMR spectrum shown on the top is used as a reference for starting materials, catalyst, and product ......................................................................................................................... 43 15. Figure 3.4. Proposed catalytic cycle for the hydrosilylation of 2a and 3a by 1e.. 45 16. Figure 4.1. Hammet plots for 1e-catalyzed hydrosilylation and corresponding 4-X-styrene derivative (X = OMe, F, or CF3) to form a mixture of complexes A and B ................ 49 17. Figure 4.2. 1H NMR monitoring of the hydrosilylation of 2c and 3a by 1e over time at 75 °C ................................................................................................................................ 51 18. Figure 4.3. 1H NMR monitoring of the hydrosilylation of 2a and 3a by 1e over time at 75 °C ................................................................................................................................ 52 19. Figure 4.4. Visual Kinetic Analysis experiments: (a) reaction scheme, (b) time adjusted kinetic profile overlap of experiments A and B, (c) time adjusted kinetic profile overlap of experiments A and C .................................................................................................... 53 20. Figure 4.5. VT NMR spectra of 1k recorded in C6D6 at various temperatures (25-95 °C) ................................................................................................................................ 54 21. Figure 4.6. (a) Library of (NHC)Ni(styrene)2 complexes tested with the corresponding steric (%VBur) and electronic (TEP) parameters for each NHC. TEP, Tolman electronic parameter are measured in cm-1. (b) (NHC)Ni(styrene)2-catalyzed hydrosilylation monitored by GC using mesitylene or durene as an internal standard. Error bars are omitted for clarity ......... 56 22. Figure 4.7. Left: CV data for complexes 1e, 1k, 1m, 1n, and 1o. Right: Ni complex of interest, the voltage corresponding to the first oxidation (Ni0/NiI) followed by the second oxidation (NiI/NiII) ....................................................................................................................... 58 23. Figure 5.1. (a) Remote hydrosilylation of a terminal alkene and a 3° silane catalyzed by a transition metal complex. (b) Example of a branched-selective remote hydrosilyation catalyst in the literature. (c) This work on remote hydrosilylation utilizing (NHC)Ni cataylsts.. 61 24. Figure 6.1. a) Alkene isomerization. (b) Types of heterogeneous catalysts for alkene isomerization. (c) Ni/H2SO4 generation and decomposition. (d) This work: development of Ni/SZO300 for alkene isomerization ............................................................................. 69 25. Figure 6.2. (a) Comparison of the acid sources (H+) in isomerization of 1c to 2c. Conditions: allylbenzene (1c, 0.13 mmol, 1.0 equiv), Ni[P(OEt)3]4 (0.0036 mmol, 3.0 mol %), H + (0.0062 mmol, 5.0 mol %), and Et2O (2.0 mL). (b) Hot-filtration experiment. ........................ 74 13 26. Figure 6.3. (a) Catalyst aging study of Ni/H2SO4 (blue squares) and Ni/SZO300 (green diamonds). Conditions: 1c (0.12 mmol, 1.0 equiv), Ni[P(OEt)3]4 (0.0036 mmol, 3.0 mol %), H2SO4 or SZO300 (0.0060 mmol H +, 5.0 mol %), and Et2O (2.0 mL). (b) Catalyst recyclability study for the isomerization of 1c. ................................................................................................ 76 27. Figure 6.4. (a) Substrate scope for isomerization using Ni/SZO300. Isolated yields and selectivity (E/Z) of the isolated products are reported. The selectivity was determined by relative integrations in the 1H NMR. Conditions: 1 (1.0 mmol, 1.0 equiv), Ni[P(OEt)3]4 (0.030 mmol, 3.0 mol %), SZO300 (0.050 mmol H +, 5.0 mol %), Et2O (17 mL), 30 °C, 1-24 h. (b) Substrate scope with Ni/H2SO4. Conversion is reported as % conversion to product. Conversion and selectivity were determined by GC or GC-MS ............................................................................. 79 28. Figure 6.5. Kinetic analysis of Ni and Pd isomerization catalysts. ....................... 82 29. Figure 6.6. [Ni–H]+-catalyzed reactions under unoptimized conditions. (a) Hydroalkenylation of styrene to afford 3a. (b) hydroboration of 2u and B2Pin2 to afford 3b. (c) Hydrosilylation of styrene and H2SiPh2 to afford 3c.. ............................................................................... 85 14 LIST OF TABLES Table Page 1. Table 5.1. Solvent screen for the hydrosilylation of B-2b and 3a by ITMe/Ni(COD)(DQ) ................................................................................................................................ 65 2. Table 6.1. Evaluation of acid sources for the isomerization of 1a to 2a ............... 72 15 LIST OF SCHEMES Scheme Page 1. Scheme 1.1. Catalytic cycle of the Chalk-Harrod mechanism .............................. 22 2. Scheme 1.2. Hydride insertion/elimination reaction mechanism of (NHC)Ni-catalyzed alkene hydrosilylation of styrene and H2SiPh2........................................................................ 25 3. Scheme 1.3. Remote hydrosilylation of a terminal long-chain alkene to install a silicon group at the most internal position ......................................................................................... 25 4. Scheme 3.1. Possible transition metal-catalyzed hydrosilylation mechanisms: (a) Chalk- Harrod mechanism, (b) modified Chalk-Harrod mechanism, and (c) a radical mechanism. ................................................................................................................................ 37 5. Scheme 3.2. 1e-catalyzed hydrosilylation of a 1,6-diene 2s and 3a. Conditions: 2s (0.87 mmol, 1.0 equiv), 3a (0.96 mmol, 1.1 equiv), 1e (0.044 mmol, 5.0 mol %), toluene (4.0 mL), 100 °C, 4 h, under N2 ................................................................................................................... 38 6. Scheme 5.1. NHC screen for the isomerization of 1a to 2a by Ni(COD)2/NHC/HSiPh3 ................................................................................................................................ 63 7. Scheme 5.2. Evaluation of Ni(0) precatalysts for the isomerization of 2a to A-2a and B-2a ................................................................................................................................ 64 8. Scheme 6.1. Mechanistic experiments. (a) Reactivity with vinylcyclopropane (1ac). (b) Reactivity with a 1,6-diene (1ad). (c) Crossover experiment between 1a and 1c-dn. . 85 16 CHAPTER I THE DEVELOPMENT AND APPLICATION OF TRANSITION METAL–HYDRIDES IN CATALYSIS FOR ALKENE HYDROSILYLATION AND ISOMERIZATOIN REACTIONS This chapter was written by Alison Sy-min Chang and presents an unpublished perspective on work developed and presented in Chapters II-VI. 1.1 Introduction Transition metal-catalyzed organic reactions are effective routes to access precursors for various types of materials and pharmaceutical compounds. Specifically, the importance of metal- hydride (M–H) motifs within these reactions cannot be understated. Some valuable examples of M–H utilized in industry are (1) the Shell Higher Olefin Process1, a Ni–H mediated reaction that oligomerizes ethylene into α-olefins on a one million tonne scale annually (Figure 1.1.a.), (2) the polymerization of 1-alkenes into various thermoplastics for consumer goods (e.g., polyethylene, polypropylene, and others) mediated by a Zr–H complex known as a Zeigler-Natta catalyst2, (Figure 1.1.b.), and (3) the hydroformylation of syngas and ethylene promoted by a Rh–H catalyst3–5, known as the oxo process (Figure 1.1.c.). In addition to such valued catalytic processes, the mechanism by which these catalysts operate is also of great significance. Unveiling these catalytic pathways is an effective way to inform future catalyst design to inhibit byproduct formation, increase reaction efficiency, and obtain high product selectivity. This often results in metal and ligand sphere tuning to induce specific reactivity. An elegant study that establishes a structure-activity relationship through ligand modification from our group is a (NHC)Ni/HSiAr3-catalyzed (NHC = N-heterocyclic carbene, Ar = aryl) alkene isomerization system.6 The silane is required to generate an active Ni–H species through the oxidative addition of the H–Si bond to the Ni(0) center. The systematic alteration in sterics of the NHC led to the realization that a bulky NHC is more compatible with smaller alkenes. On the contrary, a smaller NHC is well-suited for sterically hindered trisubstituted alkenes because the substantial coordination site can not only promote substrate binding, but also faster migratory 17 Figure 1.1. Examples of M–H in industry for the following reactions: (a) Shell Higher Olefin Process, (b) polymerization of α-olefins, and (c) hydroformylation. Ph, phenyl. Figure 1.2. Catalyst tuning of: (a) ligand modulation for an alkene isomerization catalyst, and (b) metal modulation for an allene hydrosilylation catalyst. Ph, phenyl; Ar, aryl; Me, methyl; Et, ethyl. 18 insertion (Figure 1.2.a.).7 Additionally, further electronic adjustment of the HSiAr3 resulted in faster reaction kinetics with more electronic withdrawing groups appended to the silane aryl substituents (Figure 1.2.a.). Work by Montgomery and co.8 showcases reversed catalyst regioselectivity for allene hydrosilylation simply by changing the metal identity from Pd to Ni (Figure 1.2.b.). These results highlight how critical catalyst tuning and mechanistic determination is in aiding reaction development. Furthermore, the prevalent use of M–H in various catalytic processes give rise to their potential for various hydrofunctionalization applications. Our group is particularly interested in developing Ni catalysts that can readily form a Ni– H. We specifically target the investigation of Ni due to its Earth abundance and versatile reactivity, as Ni catalysts have been documented to undergo both one- and two-electron pathways, which is heavily influenced by both the ligand coordination sphere and reaction conditions. Due to these factors, Ni can be a sustainable alternative to Pd and Pt catalysts. The widespread use of Ni in both homogeneous and heterogeneous transformations provides us with strong motivation to investigate organic transformations mediated by Ni catalysis such as alkene isomerization and hydrosilylation. When the two reactions are paired together, the isomerization of alkenes followed by the hydrosilylation of the newly synthesized alkene is an attractive method to obtain value-added products from a reaction known as remote hydrosilylation. This type of reactivity can also be applied to other types of hydrofunctionalization reactions if the catalyst(s) are compatible. Remote functionalization can be mediated by a single catalyst that performs both transformations or by two separate catalysts having their unique function, either in a single pot or in tandem with one another. One example of an applied remote functionalization reaction is an intermediate step in the preparation of Nylon 6,6, known as the DuPont adiponitrile synthesis (Figure 1.3.).9 This Ni[P(OAr)3]4-catalyzed reaction forms an active Ni–H species from the oxidative addition of HCN to Ni. After the hydrocyanation of one equivalent of HCN to butadiene (step i), the internal alkene that is formed is then isomerized to the terminal alkene (step ii) prior to a second equivalent of hydrocyanation (step iii). The product of this reaction is then further reduced and polymerized to form the desired product, Nylon 6,6. Remote functionalization is a powerful method to install a functional group distal to the initial reaction site using accessible precursors (e.g., terminal vs. internal alkenes) to generate valuable products that cannot otherwise be achieved. 19 Figure 1.3. Dupont adiponitrile process catalyzed by a homogeneous Ni–H species. Ar, aryl. Having versatile activity, Ni is a promising candidate to develop catalytic systems with. This thesis will convey the utility of Ni catalysis in separate homogeneous and heterogeneous systems for various organic transformations. 1.2 Pt–H and Ni–H in Alkene Hydrosilylation Alkene hydrosilylation, the addition of a H–Si bond across a π-bond, is a widespread reaction owing to its prevalence in the silicone industry (Figure 1.4.a.).10 This metal-mediated reaction has led to the development of various catalyst designs, including the initial discovery of Speier’s catalyst, H2PtCl6/i-PrOH (Figure 1.4.b.). 11 This linear-selective Pt catalyst spurred the initial development of the silicone industry; however, due to long induction periods prior to catalyst activation, a dangerously exothermic process on a large scale, this catalyst has mostly been replaced by Karstedt’s catalyst, Pt2(DVTMS)3 (DVTMS = 1,3-divinyl-1,1,3,3- tetramethyldisiloxane, Figure 1.4.b.). Karstedt’s catalyst has truly advanced the hydrosilylation reaction to its current state in industry and is the most widespread hydrosilylation catalyst to date. The use of Karstedt’s catalyst has expanded silane compatibility and catalyst activation is less harsh compared to Speier’s catalyst. Although only a small amount of Karstedt’s catalyst is required for hydrosilylation reactions (ppm-ppb amounts depending on the reagent)10, the incredibly fast reaction kinetics of the catalyst often leads to undesirable side reactions (e.g., isomerization, hydrogenation, and dehydrogenative silylation).12 Due to the extremely high activity of Karstedt’s catalyst, extensive work has been dedicated to reveal the reaction mechanism. Karstedt’s catalyst was found to proceed through the Chalk-Harrod mechanism, by which a Pt–H intermediate is the active catalyst and is formed by the oxidative addition of H–Si 20 to the Pt(0) precatalyst (Scheme 1.1.).13 Catalyst stability was found to be dependent on excess alkene in solution to inhibit colloidal Pt formation, which are postulated to be responsible for side reactivity. The findings from these mechanistic experiments give rise to further optimization of reaction conditions to inhibit catalyst decomposition, demonstrating the importance of understanding how a catalyst facilitates a reaction. Despite the high activity of Karstedt’s catalyst, further work to prepare improved hydrosilylation catalysts to inhibit catalyst decomposition led to the discovery of Markό’s catalyst, (NHC)Pt(VTMS) (NHC = N-heterocyclic carbene, VTMS = vinyltetramethyldisiloxane, Figure 1.4.b.).12 Indeed, the presence of the strongly σ-donating ligand, an NHC, alleviates catalyst decomposition routes and thereby hinders byproduct formation. The tunable sterics of the NHC substituents trend with regioselectivity, and the functional group compatibility of Markό’s catalyst can be expanded from that of Karstedt’s catalyst to include expoxy groups. Despite the progress in Pt hydrosilylation development, much work has been devoted to developing hydrosilylation catalysts with Earth-abundant metals such as Ni, as an alternative. With the affordable cost associated with Ni in comparison to Pt and its versatile reactivity, there are several reports on the utility of Ni–H in alkene hydrosilylation. For example, Chirik and co. developed a linear-selective (α-diimine)Ni–H dimer that is proposed to undergo a one-electron process due to the redox active nature of the ligand (Figure 1.5.).14 To our knowledge, this notable finding is the only linear-selective Ni catalyst that exhibits 3° silane activation. Alternatively, several examples of branched-selective Ni–H catalysts have been reported, albeit with limitation to 1° and 2° silane activation. For example, Schmidt and co. document the synthesis of a series of (P,N-ligand)Ni complexes that mediate alkene hydrosilylation activating 1° and 2° silanes with preliminary mechanistic studies alluding to the formation of a Ni–H active species (Figure 1.5.).15 Additional systems by Zargarian and co.16,17 and Valerga and co.18 tentatively show that an (indenyl)Ni and a (picolyl-NHC)Ni complex, respectively, generate a Ni–H active species for alkene hydrosilylation with H3SiPh, a 1° silane (Figure 1.5.). Motived by the lack of branched- selective Ni hydrosilylation catalysts able to activate 3° silanes, Chapter II of this dissertation describes the reaction development of a branched-selective (NHC)Ni(0)-catalyzed alkene hydrosilylation system that is compatible with 2° and 3° silanes (Figure 1.6.). Modulating ligand steric influences catalyst reactivity, and we show the applicability of this reactivity handle in the substrate scope. Within our substrate scope, we show an expansion in silane compatibility 21 compared to previous reports with particular use of industrially relevant 3° alkoxy- and chlorosilanes. The work on Chapter II was published in ACS Catalysis in 2022. This chapter was written by Alison Sy-min Chang with editorial assistance from Dr. Kiana E. Kawamura and Victor M. Salpino contributed synthetically through the preparation of starting materials. Hayden S. Henness contributed through rate laws experiments. Jack C. Greene contributed intellectually. Figure 1.4. (a) Alkene hydrosilylation, and (b) Pt catalysts for alkene hydrosilylation. Cy, cyclohexyl. Scheme 1.1. Catalytic cycle of the Chalk-Harrod mechanism. 22 Figure 1.5. Ni alkene hydrosilylation precatalysts with corresponding product selectivity and silane compatibility. Building upon Chapter II, Chapter III describes the mechanistic elucidation of alkene hydrosilylation using a (NHC)Ni(styrene)2 catalysts, pointing towards a metal-hydride insertion/elimination pathway (Scheme 1.2.). This chapter was written by Alison Sy-min Chang, with editorial assistance from Dr. Kiana E. Kawamura and Professor Amanda K. Cook. Dr. Kiana E. Kawamura and Victor M. Salpino contributed synthetically through the preparation of starting materials. Hayden S. Henness carried out rate law experiments. As a continuation of Chapter II and III, Chapter IV further explores the electronic structures of various (NHC)Ni(alkene)2 complexes and their relation to alkene hydrosilylation (Figure 1.7.). This is achieved by utilizing both NMR spectroscopy and cyclic voltammetry methods. Part of the work presented in Chapter III was published in ACS Catalysis in 2022 and written by Alison Sy- min Chang, with editorial assistance from Dr. Kiana E. Kawamura and Professor Amanda K. Cook. Dr. Kiana E. Kawamura and Victor M. Salpino contributed synthetically through the preparation of starting materials. The remaining unpublished work in Chapter III was developed and experimentally carried out by Alison Sy-min Chang. As previously mentioned, remote hydrosilylation is a commanding tool to obtain internally functionalized alkenes. Therefore, we took advantage of our newly established (NHC)Ni-catalyzed alkene hydrosilylation system described in Chapters II-IV and coupled it with alkene isomerization to induce remote hydrosilylation described in Chapter V (Scheme 1.3.). Remote hydrosilylation is a process that installs a silicon group at a position distal to the initial reaction site. The work in Chapter V was developed by Alison Sy-min Chang and Professor Amanda K. Cook and the synthetic and catalytic system development was carried out by Cailey Carpenter, Gaby Bailey, and 23 Alison Sy-min Chang. This chapter was written by Alison Sy-min Chang, with editorial assistance from Cailey Carpenter and Professor Amanda Cook. 1.3 Heterogeneous Ni Alkene Isomerization Catalysts Several homogeneous Ni isomerization catalysts have been developed, in conjunction with extensive mechanistic studies to elucidate the reaction pathway.19,20,14,21,6 Although, the field is dominated by precious metal catalysts due to their significantly higher activity. Furthermore, limited progress has been made in the field of heterogeneous alkene isomerization catalysts despite the practical use of recyclability. This lack of progress is largely influenced by the uncontrolled nature by which these complexes are prepared, making their active sites indiscernible. Select examples by Kegnæs and co. show alkene isomerization facilitated by Ni/Co nanoparticles encapsulated in nitrogen-doped carbon shells.22 However, stoichiometric amounts of HSiEt3, elevated temperatures (140 °C), and high catalyst loading (8 mol % Co/Ni) are all required for full conversion to product. Other examples of solid Nicatalysts active for alkene isomerization are Ni2P/SiO2–Al2O3 activated by LiAlH 23 4 , Ni/MCM-41 or Ni/AlMCM-41 24, H2-reduced NiO/Cr 252O3 , and NiNaY modified by picolinic acid or NaOH 26. Notably, these solid catalysts are prepared in a crude fashion, making the catalytic sites indiscernible and often leading to low selectivity, yield, and undesirable byproduct formation. To alleviate these factors, we have prepared a modular heterogeneous Ni–H catalyst using a surface organometallic chemistry (SOMC) method described in Chapter VI of this thesis. SOMC applies molecular organometallic Figure 1.6. Development of a branched-selective (NHC)Ni-catalyzed alkene hydrosilylation system to activate 2° and 3° silanes. 24 Scheme 1.2. Hydride insertion/elimination reaction mechanism of (NHC)Ni-catalyzed alkene hydrosilylation of styrene and H2SiPh2. Figure 1.7. Exploration of the electronic structures of (NHC)Ni(alkene)2 complexes. Scheme 1.3. Remote hydrosilylation of a terminal long-chain alkene to install a silicon group at the most internal position. principles onto a heterogeneous system. Using these principles with the intention to translate a previously developed molecular [Ni–H]+-mediated alkene isomerization system developed by 25 Cramer and Lindsay19, we can obtain the desired [Ni–H]+ scaffold via protonation of the Ni(0) precursor with a solid acid, namely sulfated zirconia. This newly generated species was found to be active for alkene isomerization. We show that this solid catalyst can tolerate a wide range of functional groups, is highly recyclable, and can also be applied to various hydrofunctionalization reactions (Figure 1.8.). Chapter VI includes unpublished work done by Alison Sy-min Chang as well as submitted and co-authored material from Chang, A. S.; Kascoutas, M. A.; Valentine, Q. P.; How, K. I.; Thomas, R. M.; Cook, A. K. Alkene Isomerization using a Heterogeneous Nickel– Hydride Catalyst. Submitted. This article was written by Alison Sy-min Chang, with editorial assistance from Melanie A. Kascoutas and Professor Amanda K. Cook. Melanie A. Kascoutas and Kiera I. How contributed synthetically through the preparation of starting materials. Quinn P. Valentine and Rachel M. Thomas performed preliminary work to establish the project. 1.4 Conclusions and Outlook M–H motifs are often highlighted throughout catalysis through the application in various organic transformations ranging from alkene isomerization to hydrofunctionalization reactions. These critical catalytic intermediates are utilized in industrial reactions, as determined through experimental mechanistic realizations. The frequent use of M–H motifs within catalysis highlights the importance of such scaffolds, deeming them as noteworthy intermediates to investigate. Figure 1.8. Proposed heterogeneous Ni–H catalyst capable of undergoing alkene isomerization and hydrofunctionalization reactions. 26 CHAPTER II DEVELOPMENT OF A (NHC)Ni(0)-CATALYZED ALKENE HYDROSILYLATION SYSTEM USING 2° AND 3° SILANES This chapter includes previously published and co-authored material from Chang, A. S.; Kawamura, K. E.; Henness, H. S.; Salpino, V. M.; Greene, J. C.; Zakharov, L. N.; Cook, A. K. (NHC)Ni(0)-Catalyzed Branched-Selective Alkene Hydrosilylation with Secondary and Tertiary Silanes. ACS Catal. 2022, 12, 1102–11014. https://doi.org/10.1021/acscatal.2c03580. This article was written by Alison Sy-min Chang, with editorial assistance from Dr. Kiana E. Kawamura and Professor Amanda K. Cook. Dr. Kiana E. Kawamura and Victor M. Salpino contributed synthetically through the preparation of starting materials. Hayden S. Henness carried out rate law experiments. Jack C. Green contributed intellectually. 2.1 Introduction As one of the most industrially valuable transition metal-catalyzed reactions, the hydrosilylation of π-bonds supplies the feedstock to produce silicon-based materials (Figure 2.1.a.).27–31 These products have widespread applications in both organic and materials chemistry32 and are utilized to yield high-value durable organosilicon materials,27–31 silicon-based cross- coupling agents,33–35 alcohol precursors,36–38 and pharmaceuticals.39–41 The tremendous advancement of the silicone industry is owed to the discovery of the highly active, linear-selective, platinum catalysts, particularly Karstedt’s catalyst [Pt2(dvtms)3] (dvtms, 1,3- divinyltetramethylsiloxane).42,30 Because Pt is one of the most expensive metals and much of the Pt used in silicone production is unrecoverable,31 there is a strong desire to shift the reliance on Pt to more Earth-abundant metal catalysts. Catalysts composed of base metals31,43–45 like Ni,46–52,14,53–57 Mn,58–64 Co,65–85 and Fe86– 96,68,97–106 have been developed for linear-selective alkene hydrosilylation. As a congener of Pt, Ni is especially promising as a base metal candidate for alkene hydrosilylation. Ni(II) complexes possessing pincer,49,51,55 salicylaldiminato,48 allyl,50 amido,47 and acetylacetonato52,54 ancillary ligands and no added ligand56 exhibit high linear selectivity for the hydrosilylation of alkenes with 27 Figure 2.1. (a) General scheme of transition metal-catalyzed hydrosilylation. (b) Base metal- catalyzed hydrosilylation catalysts. (c) Our proposed strategy to investigate the mechanism of (NHC)Ni(0) complexes to yield branched organosilicon products using 2° and 3° silanes. primary (1°) or secondary (2°) silanes. Expansion to tertiary (3°) silanes has been a recent focus due to the relevance in industrial hydrosilylation,44 and particularly important advances have been made using alkoxy-substituted silanes to form the linear hydrosilylation products with exceptional regioselectivity. 27,30,35,43,45,46,48,56,64,66,67,73 Despite these advances, most reports focus on 1° and 2° aryl silanes, emphasizing the need to develop catalysts that enable the hydrosilylation of 3° silanes, especially chloro- and alkoxy-substituted silanes (Figure 2.1.b.). Notably, only a handful of base metal catalysts have been developed to react with chlorosilanes, and all of them either give poor selectivity or have limited scopes.107,86,108,109,55 Indeed, investigation and expansion of the silane scope is often neglected in hydrosilylation reactions, despite the fact that both changes in the 28 silane’s electronic110–112 and steric113,111,114,115 characteristics impact reactivity and properties of hydrosilylation products. Another challenge in hydrosilylation lies in accessing branched organosilicon products, which has been substantially less developed than that of linear-selective systems.116,117 Branched organosilicon products are valuable and are highly sought out for the production of adhesion promotors, RTV silicone additives, and silicone coatings,27 as well as in the enantioselective synthesis of therapeutic agents.28 In the emergent field of base metal-catalyzed branched-selective alkene hydrosilylation, noteworthy work achieving high regioselective control employ Mn,61 Co,98,72,118,103,84 Fe,102,119 Ni,16–18,15 and Cu120 complexes that readily react with 1° silanes. Even fewer examples enabling activation of 2° silanes have been reported.120,77,15,82,83,57,85 To our knowledge, examples with 3° silanes are limited to the (pincer)Co-catalyzed hydrosilylation of 1- octene using (EtO)3SiH 98 and the ([P~C]-chelate)Co-catalyzed hydrosilylation of styrene with Ph3SiH and Me(EtO)2SiH. 83 A significant challenge remaining in base metal-catalyzed alkene hydrosilylation is the synthesis of branched hydrosilylation products using 3° silanes with alkyl-, aryl-, alkoxy-, or chloro-substituents (Figure 2.1.b.). An additional deficit in the literature is a fundamental understanding of the silane’s steric and electronic properties on hydrosilylation.44 Previous work on Pt catalysts exploit electronically diverse silanes to illuminate the impact on hydrosilylation reactivity, giving rise to key mechanistic insights.121,110,111,122 Our group has recently investigated the effect of silane electronics112 and sterics115 on oxidative addition of Si–H bonds to Pd(0). While these reports offer foundational information on hydrosilylation using precious metal catalysts, analogous studies have not been carried out using catalysts with base metals. Herein we report a Ni-catalyzed, branched-selective hydrosilylation system employing alkenes and 2° or 3° silanes. Taking inspiration from Montgomery’s seminal work on (NHC)Ni- catalyzed allene8,123 and alkyne124 hydrosilylation systems, we demonstrate that structurally defined (NHC)Ni(0)125,126 complexes are active for the branched-selective hydrosilylation of alkenes with both 2° and 3° silanes with broad electronic and steric scopes including the use of alkoxy- and chlorosilanes (Figure 2.1.c.). We additionally report mechanistic findings that establish a two-electron pathway proceeding via an insertion/elimination pathway. Data that 29 support our proposed mechanism were obtained using isotopic labeling studies, rate law determination, Hammett analyses, and ligand exchange experiments. 2.2 Results and Discussion Catalyst Ligand Design Our investigations commenced with evaluation of the effect of the NHC substituents on the hydrosilylation of styrene (2a) and H2SiPh2 (3a). Using (NHC)Ni(dvtms) derivatives 1a-1c (Figure 2.2.) enabled steric variation of the NHC while keeping the supporting alkenyl ligands unchanged.127,128 We hypothesized that smaller ancillary ligands would lead to more branched product, so we chose three readily synthesizable complexes: (ITMe)Ni(dvtms) (1a), (IMes)Ni(dvtms) (1b), and (IPr)Ni(dvtms) (1c). The %Vbur values of the corresponding ligands are a reflection of the steric imposition of the ligands and are in the ascending order of: ITMe (26.1) < IMes (36.5) < IPr (44.5) (values taken from ref. 129 at an M–C bond length of 2.00 Å).129 As hypothesized, the catalyst with the smallest NHC, 1a, gave the highest selectivity for the branched product (l/b = 1:2.0, 56% yield 4aa), and the catalyst with the largest NHC, 1c gave the lowest selectivity (l/b = 1:1.2, 12% yield 4aa) (Figure 2.2.), with the medium-sized NHC complex (IMes)Ni(dvtms) giving intermediate selectivity and yield (l/b = 1:1.5, 21% yield 4aa). We next assessed the impact that the supporting alkene ligand has on reactivity and selectivity. We chose (IMes)Ni complexes as the platform from which to study the effect of alkenes because a library of (IMes)Ni(alkene)2 complexes are known and readily synthesized. 130,125,126 Of the (IMes)Ni(alkene)2 complexes we tested, (IMes)Ni(styrene)2 (1e) gave the highest yield (l/b = 1:3.3, 49% yield 4aa) and (IMes)Ni(1,5-hexadiene) (1d) gave the best selectivity (l/b = 1:8.1, 29% yield 4aa). Attempts to combine the best NHC (ITMe) and the best supporting alkene (1,5- hexadiene or styrene) to form a discrete Ni complex, (ITMe)Ni(1,5-hexadiene) or (ITMe)Ni(styrene)2, were unsuccessful; therefore, we proceeded to optimize the reaction conditions using 1e, since it is easily synthesized and gave good yield and selectivity under unoptimized conditions. The reaction conditions were optimized to be 100 °C in toluene and using catalyst 1e, product 4aa was formed in 95% yield with exceptional branched selectivity of 1:>99 (l/b) (see Appendix A for full optimization). 30 Figure 2.2. Hydrosilylation screen of 2a and 3a at 70 °C in toluene with a series of (NHC)Ni(dvtms) complexes to yield 4aa (dvtms = 1,3-divinyltetramethyldisiloxane). Conditions: styrene (2a, 0.088 mmol, 1.0 equiv), H2SiPh2 (3a, 0.088 mmol, 1.0 equiv), (NHC)Ni(dvtms) (0.0044 mmol, 5.0 mol %), and toluene (0.40 mL). Selectivity and yields are determined by GC- MS analysis using mesitylene or durene as an internal standard. Substrate Scope With optimal conditions decided, we investigated the compatibility of complex 1e with different alkene and silane substrates. Preliminary results reveal that pre-coordinated styrene on 1e underwent hydrosilylation during what we hypothesize is catalyst activation, motivating us to use a slight excess of silane (1.1 equiv relative to added alkene). A series of 4-substituted styrene derivatives spanning across electron-donating (2a-e) and electron-withdrawing (2f,g) groups were well-tolerated in relatively high isolated yields (4aa-4ga, 68-92%) while maintaining excellent branched selectivity (l/b = 1:≥33, Figure 2.3.). Increasing the steric bulk of the alkene (2h-j) did not hinder reactivity (isolated yields of 4ha-4ja were 71-88%) nor selectivity (l/b = 1:≥26). Substrate 2j demonstrates the catalyst’s ability to react with internal alkenes, giving product 4ja (71%, l/b = 1:>99). This catalytic system also tolerates sensitive functional groups and heteroaromatics. The acetoxy-containing substrate 2k was tolerated with moderate yield (59%) and excellent selectivity (l/b = 1:51) for 4ka. 2-Vinyl-thiophene (2l) was tolerated well and furnished 4la in a good yield of 74%, albeit with diminished yet good selectivity (l/b = 1:13) and a longer reaction time was required (24 h). We hypothesize the suppressed reaction rate results from competing coordination modes between Ni and the vinyl group versus the sulfur atom. Due 31 to the difficulty in purifying 4la away from 4aa (a byproduct of catalyst activation), catalyst (IMes)Ni(1,5-hexadiene) (1d) was used instead to avoid introducing styrene to the reaction. Formation of sulfur-containing product 4la is especially remarkable since sulfur is known to poison Pt-based hydrosilylation catalysts.31 Amino groups are also tolerated well, with 4- dimethylaminostyrene (2b) undergoing hydrosilylation in good yield (77%) with remarkable selectivity (l/b = 1:>99) to obtain product 4ba. Terminal aliphatic alkenes are also well tolerated, although the selectivity was reversed to favor the linear product (4ma-4oa). These data demonstrate the necessity of an aryl ring to obtain the branched product, alluding to the intermediacy of a Ni-benzallyl intermediate. Without the presence of an aromatic moiety to stabilize a Ni-intermediate, the regiodivergent behavior may arise from steric hinderance provided by the alkyl substituent. This substrate-dependent reversal in selectivity is precedented in base metal hydrosilylation systems.16,18,67,61,102,15,83,57,85 Illustrating the breadth of catalyst 1e to functionalize vinylarene derivatives, we further diversified the substrate scope by synthesizing a collection of electronically (3b-3e) and sterically modified diarylsilanes (3f-i) and examined their hydrosilylation reactivity with 2a. The reactivity of 1e with modified silanes maintained outstanding selectivity for the branched product (l/b = 1:>99) and achieved moderate to high isolated yields (51%-99%) to obtain products 4ab-4ae (electronic modification) and 4af-4ai (steric modification). Using H2SiEt2 (3j) in place of a diarylsilane proved to be quite successful, yielding 94% of 4aj while preserving excellent selectivity (l/b = 1:20). Having shown a wide range of 2° silanes to be effective in the hydrosilylation of alkenes, we next applied this catalytic system to 3° chlorosilanes, which are particularly relevant for industrial applications. We were pleased to find that 1e is catalytically active for the hydrosilylation of 2a and chlorosilanes (3r-s) to give 4ar-4as in excellent yields (77-84%) and high branched selectivity (l/b = 1:>99). Hexanes was used in place of toluene as the reaction solvent for ease of product purification. Chlorosilanes are often not tolerated (or not investigated) in hydrosilylation reactions, and it has been demonstrated that early Ni-based catalysts enable the exchange of Si–Cl bonds for Si–H bonds, with the reduced products often being the major product.107,108 The inclusion of chlorosilanes in the substrate scope is a significant advance, particularly in light of their relevance to polysiloxane chemistry. 32 In pursuit of expanding the identity of 3° silanes, we tested the hydrosilylation of triarylsilanes (3k-m) with 2a using catalyst 1e. 1e indeed proved to be catalytically active for the hydrosilylation of HSiPh3 (3l) and HSi(4-CF3-C6H4)3 (3m) with 2a (74% yield, l/b = 1:>99 and 79% yield, l/b =1:>99, respectively), however not with HSi(4-OMe-C6H4)3 (3k). Additionally, employing 3° silanes with one or more alkyl or alkoxy substituents (HSiPh2Me (3n), HSiPhMe2 (3o), HSi(OEt)3 (3p), and HSi(Me)(OSiMe3)2 (3q)) also proved to be unproductive using catalyst 1e. These results encouraged us to revisit our catalyst’s structure-activity relationship by modifying the steric bulk of the NHC ligand. We postulated that a less sterically bulky ligand (ITMe vs. IMes) would permit the hydrosilylation of challenging alkyl- and alkoxy-substituted silanes with 2a. Due to the difficulty in elucidating the structure of the product formed in the attempted synthesis of (ITMe)Ni(styrene)2, we hypothesized that the active catalyst could be formed in situ through the introduction of Ni(cod)2 and ITMe (Figure 2.3.). This approach offers a practical alternative to isolation of an (NHC)Ni(alkene)2 complex, and excitingly, enabled the formation of products 4ak- ao formed from the hydrosilylation of 2a with the challenging 3° silanes in good to excellent yields (74-94%) with branched selectivity (l/b = 1:>99). Like chlorosilanes, 3° alkoxy-substituted silanes are particularly relevant for industrial applications. Notably, alkoxy-substituted silanes (3p, 3q) are also tolerated well under our conditions, forming products 4ap and 4aq in good yield (both 62%) and excellent branched selectivity (both l/b = 1:>99). Beyond vinylarene substrates, an aldehyde (2p) and ketones (2q, 2r) readily reacted with HSiPh3 (3l) to form 4pl, 4ql, and 4rl, respectively, in high yields (94-99%) with only the O–silyl product formed. Overall, the scope of silanes and alkenes that undergo hydrosilylation demonstrate the broad utility of this (NHC)Ni(0) catalyst system. We further show that the steric bulk of the NHC can be tuned to enhance yields with particularly unreactive silanes. 2.3 Conclusion and Outlook Low-valent (NHC)Ni complexes are active pre-catalysts for the branched-selective hydrosilylation of olefins. Notably, the catalytic system developed is compatible with 3° silanes, including industrially relevant alkoxy- and chloro-containing silanes. The ability to use 3° silanes was accomplished through construction of a ligand structure-activity relationship: more sterically demanding silanes required a sterically smaller ancillary ligand, ITMe. A practical approach to 33 Figure 2.3. Scope of alkene hydrosilylation 34 Isolated yields and selectivity (l/b) determined by relative integrations in the 1H NMR are reported. Selectivity values in parentheses are determined by GC or GC-MS from the crude reaction mixture before purification and represent inherent catalyst selectivity. Conditions: 1e (0.05 mmol, 5 mol %) or Ni(cod)2 (0.05 mmol, 5 mol %) and ITMe (0.05 mmol, 5 mol %), alkene (2a-2r, 1.0 mmol, 1.0 equiv), silane (3a-3s, 1.1 mmol, 1.1 equiv), toluene (4.6 mL or 0.42 mL), 100 °C, 4 h, under N . aReaction yield determined by GC using durene as an internal standard. b2 1d was used in place of 1e. c24 h. d3 equiv 2a. e2 equiv silane. f1.25 equiv silane, hexanes. generating the (ITMe)Ni(0) pre-catalyst in situ was developed to expand reactivity. A larger NHC ligand, IMes, was found to be optimal for 2° silanes. Both sterically and electronically diverse silanes and styrenes are tolerated well, giving high selectivity for the branched product (often 1:>99, l/b) in good-to-excellent yields. Even functional groups like aryl esters and methoxy groups, which often react with low-valent Ni, are well-tolerated. 35 CHAPTER III MECHANSITIC INVESTIGATION OF A HOMOGENEOUS (NHC)Ni(0)-CATALYZED ALKENE HYDROSILYLATION SYSTEM This chapter includes previously published and co-authored material from Chang, A. S.; Kawamura, K. E.; Henness, H. S.; Salpino, V. M.; Greene, J. C.; Zakharov, L. N.; Cook, A. K. (NHC)Ni(0)-Catalyzed Branched-Selective Alkene Hydrosilylation with Secondary and Tertiary Silanes. ACS Catal. 2022, 12, 1102–11014. https://doi.org/10.1021/acscatal.2c03580. This article was written by Alison Sy-min Chang, with editorial assistance from Dr. Kiana E. Kawamura and Professor Amanda K. Cook. Dr. Kiana E. Kawamura and Victor M. Salpino contributed synthetically through the preparation of starting materials. Hayden S. Henness carried out rate law experiments. Jack C. Greene contributed intellectually. 3.1 Introduction The Chalk-Harrod mechanism is the widely accepted reaction pathway for the hydrosilylation of alkenes by Pt catalysts (Scheme 3.1.a.).131,29,13 The mechanism is comprised of four steps: i) oxidative addition of the H–Si bond to the Pt center, ii) olefin coordination, iii) olefin insertion into the Pt–H bond (which is both the regioselectivity- and rate-determining step13), and iv) reductive elimination of the organosilicon product. Alternatively, the modified Chalk-Harrod mechanism is often invoked to explain how the branched isomer forms; in this mechanism, the olefin inserts into the Pt–Si bond (Scheme 3.1.b., step iii) instead of the Pt–H bond.132,67 Xie and Fan,133 who carried out mechanistic studies using a computational approach on Montgomery’s (NHC)Ni-catalyzed (NHC = IPr or IPr*OMe) hydrosilylation of allenes,8,134 determined that the hydrosilylation of allenes proceeds via the modified Chalk-Harrod method with a ligand-to-ligand silyl transfer into the double-bond of the allene as the rate-determining step (RDS).133 As is common with base metal catalysts, radical pathways must also be considered. Typically, the linear products of hydrosilylation are formed when a radical mechanism is operating;29,54,63 this selectivity is due to the formation of a silyl radical, which then reacts with the alkene to give the more stable secondary alkyl radical; after H-atom abstraction from the metal-hydride, the linear 36 product is formed (Error! Reference source not found..c.).29 Because fewer reports of branched-s elective hydrosilylation exist than linear- Scheme 3.1. Possible transition metal-catalyzed hydrosilylation mechanisms: (a) Chalk-Harrod mechanism, (b) modified Chalk-Harrod mechanism, and (c) a radical mechanism. selective hydrosilylation, there is little insight into the mechanism of branched-selective hydrosilylation of alkenes. We therefore sought to answer the following mechanistic questions: 1) does the reaction proceed through a one- or two-electron pathway? 2) what is the impact of the silane substituents on reactivity? 3) how do alkene electronics affect (NHC)Ni stability and reactivity? and 4) what are the rate-determining steps (RDSs)? 3.2 Results and Discussion One-Electron versus Two-Electron Pathway Initial experiments were designed to identify whether 1e is participating in a one- or two- electron pathway. We first monitored the formation of 4aa using catalyst 1e over time, both in the presence and absence of a radical trap: 1.1 equiv 1,1-diphenylethylene (DPE). If the hydrosilylation proceeds through an uncaged radical pathway (e.g., if either the silyl radical and/or 37 the alkyl radical depicted in Scheme 3.1.c. are uncaged), we hypothesized that the radical would diffuse and be trapped by DPE; this hypothesis assumes that the rate of diffusion of the radicals is Scheme 3.2. 1e-catalyzed hydrosilylation of a 1,6-diene 2s and 3a. Conditions: 2s (0.87 mmol, 1.0 equiv), 3a (0.96 mmol, 1.1 equiv), 1e (0.044 mmol, 5.0 mol %), toluene (4.0 mL), 100 °C, 4 h, under N2. faster than that of recombination. Addition of DPE did not affect the rate of formation or yield of 4aa (Appendix C, section C.1.7.a.), nor was DPE active as a substrate in hydrosilylation with 3a, likely due to the increased steric hinderance of DPE preventing alkene coordination to Ni. This result suggests that the mechanism is not proceeding through an uncaged radical mechanism. Additional experimentation to assess if hydrosilylation is proceeding through a radical pathway led us to react 3a with the 1,6-diene 2s. If a radical pathway is operative, the 2° alkyl radical which is expected to form upon addition of the silyl radical to the terminal alkene (Scheme 3.1.c., step ii) would undergo rapid intramolecular cyclization followed by H-atom transfer (HAT) from the Ni–H. Shown in Scheme 3.2., the reaction of 2s with 3a and catalyst 1e gave a mixture of isomerized (geometric and positional alkene isomerization), hydrogenated, and hydrosilylation products, with the major product being the terminally functionalized linear hydrosilylation product 4sa (the internal alkene remained unreacted). This reaction selectivity is consistent with the linear- selective reactivity of 1e with aliphatic substrates (e.g., see products 4ma-4oa in Figure 2.3.). No cyclized product 6a was observed by 1H NMR or GC-MS. We also do not observe cyclization that would occur from other radical pathways (e.g., HAT prior to silyl addition leading to products 6a and/or 7aa). To validate this conclusion, we independently synthesized the cyclized alkene 6a and subjected it to hydrosilylation with 3a by 1e under identical reaction conditions. 6a did not undergo hydrosilylation, nor was it observed in the hydrosilylation of 2s. The results from these two radical trap experiments are inconsistent with a radical mechanism. We continued with mechanistic studies to gain further understanding of the reaction mechanism. 38 2 2 1 1 0 0 -1 -1 -0.3 -0.1 0.1 0.3 0.5 0.7 -0.3 -0.1 0.1 0.3 0.5 0.7 σ σ Figure 3.1. Hammett plots for 1e-catalyzed hydrosilylation of (a) electronically modified diarylsilanes (3a,b,d,e) with 2a and of (b) electronically modified vinylarenes (2a,c,e-f) with 3a. Conditions: vinylarene (0.13 mmol, 1.0 equiv), diarylsilane (0.14 mmol, 1.1 equiv), 1e (0.0030 mmol, 2.5 mol %), and toluene (2.4 mL, 0.060 M), 80 °C, under N2. Yields are determined by calibrated GC analysis using mesitylene as an internal standard. Linear-Free Energy Relationships As electronic variation of both the silane and styrene derivatives were tolerated (Figure 3.3.), we next sought to quantify the electronic influence of each component on the rate of hydrosilylation. Using the method of initial rates, we first varied the electron-richness of the silane by incorporating electron-withdrawing and electron-donating groups at the 3- or 4-position of diarylsilanes (3a, c-e; Figure 3.1.a.). Using our optimized conditions, the rates of reaction were too fast to measure accurately, especially for electron-poor silanes (e.g., 3e). To decrease the rate of the reaction, we modified the reaction conditions (temperature lowered to 80 °C, catalyst loading decreased to 2.5 mol %, and decreased reaction concentration to 0.060 M), which allowed for reliable measurements of reaction rates. Hammett analysis (Figure 3.1.a.) shows that the reaction is faster with electron-poor silanes with a sensitivity coefficient of ρ = +1.6 ± 0.2. Our group has shown that oxidative addition of Si–H bonds to Pd(0) is faster and more favorable with electron-poor silanes,112 suggesting that oxidative addition is one of the RDSs in hydrosilylation. Analogous analysis with styrene derivatives (2a, c, e-g) shows a trend opposite to that of the silane: rates are faster with electron-rich alkenes, and the magnitude of the sensitivity factor is 39 log(kX/kH) log(kX/kH) smaller (ρ = -0.6 ± 0.2) than that of the silane (Figure 3.1.b.). Notably, our data are consistent with migratory insertion of vinylarenes into Rh–H135 and Nb–H136 bonds but is inconsistent with insertion into Pd–N137 and Pd–C138 bonds. These data point toward migratory insertion of the alkene into the Ni–H bond ([2,1]-insertion) operating during the catalytic cycle (Chalk-Harrod mechanism, Scheme 3.1.a.) and not insertion into the Ni–Si bond (modified Chalk-Harrod mechanism, Scheme 3.1.b.). The effect that electronic modulation of both substrates has on the observed rate of reaction provides evidence that both substrates are involved in the steps between the catalyst resting state and the RDS. Deuterium Labelling Studies Having obtained evidence supporting the Chalk-Harrod mechanism being operative (see Hammett analyses above), we next sought to support this conclusion further and to obtain a better understanding on factors influencing the regioselectivity and the reversibility of migratory insertion steps. To do so, we embarked on deuterium-labeling experiments with D2SiPh2 (3a-d2) (Figure 3.2.). Starting from the [(styrene)Ni(D)(silyl)] complex C (Figure 3.2.a.), the first step is insertion of the alkene into the Ni–D bond to form D. This intermediate can either proceed via path a or path b. Path a is direct reductive elimination to form 4aa-d2’, which leads to 100% deuterium incorporation at Si and 33% deuterium incorporation at the methyl group (the other 66% are protium originating from 2a). Path b consists of intermediate D undergoing β-hydride elimination to give E, Ni–H/Si–D scrambling via reductive elimination of Si–D and oxidative addition of Si– H to form F, migratory insertion of the alkene into the Ni–D bond to form G, followed by reductive elimination to give isotopomer 4aa-d2’’, in which 0% deuterium incorporation is expected at Si and 66% is expected at the methyl position. Notably, both pathways a and b do not predict incorporation of deuterium at the benzylic position of 4aa. If the modified Chalk-Harrod mechanism (Scheme 3.1.b.) were operative, significant D-incorporation at the benzylic position would be expected (from reversible migratory insertion/β-hydride elimination analogous to that depicted in Figure 3.2.a.), as would the formation of dehydrogenative silylation byproducts, which are not observed under our reaction conditions. The reaction between 5 mol % 1e, 1.0 equiv 2a, and 1.1 equiv 3a-d2 at 100 °C produced 4aa-d2, which was characterized and analyzed by 1H and 2H NMR spectroscopy. At the end of the 40 reaction, approximately 56% deuterium erosion was observed at the Si–D bond, 3% deuterium incorporation was detected at the benzylic position, and 45% deuterium incorporation was detected Figure 3.2. Deuterium labeling studies. a) Expected outcomes of deuterium incorporation via Chalk-Harrod pathway for hydrosilylation, b) deuterium labeling studies with 2a and 3a-d2, and c) crossover study with 2a, 3a-d2, and 3b. at the methyl position (Figure 3.2.b.). The lack of significant deuterium incorporation at the benzylic position supports our conclusion that the modified Chalk-Harrod mechanism is not 41 operative (i.e., the alkene inserts into the Ni–H and not into the Ni–Si bond). The measured deuterium distribution in 4aa-d2 alludes to both path a and path b being operative and the Chalk- Harrod mechanism as the major mechanistic pathway. To further support an insertion/elimination pathway involving alkenes formed after deuterium incorporation (E and F in Figure 3.2.a.), a crossover experiment was designed using 0.56 equiv 3a-d2 and 0.56 equiv H2Si(4-OMe-C6H4)2 (3b) reacting with 1.0 equiv 2a (Figure 3.2.c.). Deuterium crossover was indeed obtained, as determined by 1H and 2H NMR. Integration of the Si–H/D peaks gives an approximate ratio of 1.1:1 (4aa-dn/4ab-dn), as does the integration of the methyl peaks (Figure 3.2.c., Figure B.5., B.6.). This result points towards an insertion/elimination pathway. A supplementary experiment was performed to probe the reversibility of this insertion/elimination step by monitoring the hydrosilylation of 2a and 3a-d2 by 1e by in operando 2H NMR (Figure 3.3.). Heating the reaction to 75 °C for 20 min, a prominent peak at 5.60 ppm corresponding to a deuterium on the alkene in 2a appears. The growth of this peak indicates that 1e readily exchanges hydrogen and deuterium from 2a to 3a-d2 prior to 4aa formation. In addition to the peak at 5.60 ppm, the appearance of a smaller peak at 2.60 ppm at 20 min corresponds to coordinated 2a-dn on 1e. Throughout the reaction, the peaks at 2.60 and 5.60 ppm gradually disappear as they become incorporated into 4aa-dn. These result support our conclusion that migratory insertion and β-hydride elimination are reversible, and suggest that reductive elimination is the final step of the set of rate-limiting steps.138 To gather additional insight on the RDS, a kinetic isotope effect (KIE) was measured by comparing the rates of hydrosilylation of 2a with 3a or 3a-d2 at 80 °C. Using the method of initial rates, we obtained an inverse KIE of 0.64 ± 0.06. Inverse KIE values have been reported for systems with a reversible pre-equilibrium step that involves a hydride-insertion/elimination step prior to the RDS.139–141 Inverse KIEs found in C–H activation reactions result from a multistep reaction that reflects a composite of an equilibrium isotope effect (EIE) and a KIE.136,142,143 Applying this concept to our system, the observed isotope effect is a combination of EIEs and KIEs, since we showed that migratory insertion/β-H elimination and Si–H oxidative addition/reductive elimination steps are reversible. 42 Figure 3.3. 2H NMR monitoring of the hydrosilylation of 2a and 3a-d2 by 1e over time at 75 °C. 1H NMR spectrum shown on the top is used as a reference for starting materials, catalyst, and product. Conditions: 2a (0.14 mmol, 1.0 equiv), 3a (0.15 mmol, 1.1 equiv), 1e (0.013 mmol, 10 mol %), C7H8/C7D8 (9:1, 0.6 mL, 0.22 M), under N2. Rate Law Determination To further understand the reaction mechanism, we next sought to determine the reaction’s rate law (Appendix B, Section B.1.6.c.). The order of each of the reagents 2a and 3a and catalyst 1e was obtained by measuring the initial rates of reaction at varying concentrations of the reagent or catalyst. First, we measured the rate of product 4aa formation as a function of 1e concentration (2.19–21.9 mM). Under standard reaction conditions, the rates are too quick to obtain initial rates of reaction; therefore, the reaction temperature was decreased to 80 °C. The 1e-catalyzed 43 hydrosilylation of 2a and 3a displayed half order dependence on [Ni] (0.6 ± 0.1). This value is in line with previously reported, monomeric catalysts that are activated by a pre-equilibrium ligand dissociation.144–146 Next, we determined that there is an inverse order in 2a (-0.4 ± 0.1), indicating that dissociation of 2a from Ni is an important step between the catalyst resting state and the RDS.144 The influence of olefin coordination to Ni is supported by our data from the Hammett study (Figure 3.1.b.) as well as the ligand exchange equilibrium study (Figure 3.2.). Lastly, we determined that the reaction is first order (1.0 ± 0.1) in 3a, which correlates well with the reaction rate’s dependence on silane electronics (Figure 3.1.a.). Eyring Analysis To shed light on the overall kinetic barrier of the reaction, the rates of reaction were measured at temperatures between 60 and 100 °C and an Eyring plot was constructed. The following values were obtained: ΔH‡ = 20.4 ± 0.2 kcal·mol–1, ΔS‡ = -0.28 ± 0.2 cal·mol–1·K–1, and ΔG‡373K = 20.5 ± 0.2 kcal·mol –1 (Appendix B, Section B.1.6.b.). A ΔS‡ value that is close to zero suggests that the transition state of the RDS is not very ordered or disordered, which supports our conclusion that oxidative addition (step ii) and alkene coordination (step iv) are not the RDS, as both would give large, positive values of ΔS‡. The data from the Eyring plot is consistent with either migratory insertion (step iii) or reductive elimination (step v) being the RDS (Figure 3.4.). Compilation of Mechanistic Data Figure 3.4. shows the proposed mechanism that is most consistent with the data we collected. 1e enters the catalytic cycle by alkene dissociation (step i), and then oxidatively adds the silane to form an (IMes)Ni(styrene)(silyl)(H) complex (step ii). Step iii is migratory insertion of the coordinated styrene into the Ni–H bond, resulting in the (IMes)Ni(alkyl)(silyl) complex with an open coordination site, which is then filled by coordination of styrene in step iv to form the 16- electron complex, (IMes)Ni(alkyl)(silyl)(styrene). Reductive elimination (step v) of the alkyl and silyl ligands forms the C–Si bond, releases the product, and regenerates the active catalyst, (IMes)Ni(styrene)2. The radical trap experiments support our hypothesis that the reaction is not proceeding via a one-electron pathway. Monitoring the reaction by 1H NMR shows that complex 1e is the resting state when using styrene 2a as the substrate. Analysis of mixtures of 1e and electronically varied styrene derivatives shows that the alkene dissociation and coordination to Ni is rapid and 44 Figure 3.4. Proposed catalytic cycle for the hydrosilylation of 2a and 3a by 1e. reversible; additionally, the order in 2a was found to be inverse. These data support dissociation of the alkene (Figure 3.4., step i) occurring between the resting state and the RDS. (NHC)Ni complexes are known to oxidatively add Si–H bonds,147,148 supporting the viability of step ii. First- order dependence on the silane and the fact that the rate of the reaction is dependent on the electronics of the silane show that step ii is either the RDS or lies between the catalyst resting state and the RDS. The erosion of deuterium at Si in the deuterium-incorporation experiment (Figure 3.2.b.) suggests that step ii is reversible and therefore likely not the final RDS. Because of the strong σ-donation of the silyl group, making it a very strong trans influence ligand, the alkene, which is the weakest trans influence ligand, is trans to the silyl group and cis to the hydride ligand. The easiest pathway is then migratory insertion into the Ni–H. Styrene derivatives undergo [2,1]-insertion, the product of which is likely stabilized by the benzallyl 45 bonding mode. With aliphatic substrates, there is no additional electronic stabilization to favor [2,1]-insertion; therefore, sterics dominate and [1,2]-insertion occurs, leading to the linear product. Likewise, the deuterium scrambling seen in the reaction between 2a and 3a-d2 support that step iii is partially reversible. The lack of deuterium incorporation at the benzylic position in the deuterium-incorporation experiment supports our conclusion that migratory insertion of the alkene occurs with the Ni–H bond (step iii) and not the Ni–Si bond. The inverse KIE observed with 3a and 3a-d2 results from a combination of a KIE of the RDS and the EIEs of steps ii and iii. An inverse secondary KIE observed with 2a and 3a-d2 is consistent with the migratory insertion in step iii being the RDS or before the RDS due to the change in hybridization from C(sp2) in the alkene to C(sp3). The reaction’s rate law and the activation parameters determined from the Eyring analysis support the viability of migratory insertion (step iii) and/or reductive elimination (step v) being the RDS. Further confirmation from the in operando 2H NMR studies indicate that migratory insertion is highly reversible and therefore reductive elimination is indeed the RDS. Altogether, our data supports that this branched-selective hydrosilylation follows a Chalk-Harrod mechanism with migratory insertion of the alkene occurring into the Ni–H bond. 3.3 Conclusion In-depth mechanistic studies using catalyst 1e allude to a Chalk-Harrod-type mechanism in which the alkene inserts into the Ni–H bond of the (silyl)Ni–H species that forms after oxidative addition of Ni(0) to the Si–H bond of the silane. Mechanistic experiments suggest against a radical pathway being operative. The catalyst resting state is the pre-catalyst 1e, which is described in Chapter IV. The observed electronic influence of both the alkene and the silane suggests the involvement of both substrates in the RDS. This conclusion is further supported by both the ligand exchange reactions (see Chapter IV details) with 1e and electronically varied styrenes as well as the reaction’s rate law. The compilation of our mechanistic data points towards reductive elimination being the RDS. 46 CHAPTER IV INVESTIGATIONS OF (NHC)Ni(STYRENE)2 ELECTRONIC STRUCTURES AND THEIR RELATION TO ALKENE HYDROSILYLATION This chapter includes previously published and co-authored material from Chang, A. S.; Kawamura, K. E.; Henness, H. S.; Salpino, V. M.; Greene, J. C.; Zakharov, L. N.; Cook, A. K. (NHC)Ni(0)-Catalyzed Branched-Selective Alkene Hydrosilylation with Secondary and Tertiary Silanes. ACS Catal. 2022, 12, 1102–11014. https://doi.org/10.1021/acscatal.2c03580. This article was written by Alison Sy-min Chang, with editorial assistance from Dr. Kiana E. Kawamura and Professor Amanda K. Cook. Dr. Kiana E. Kawamura and Victor M. Salpino contributed synthetically through the preparation of starting materials. The unpublished work in Chapter IV was developed and experimentally carried out by Alison Sy-min Chang. 4.1 Introduction The discovery of N-heterocyclic carbenes (NHC) only three decades ago benchmarked the rapid development of various NHC-ligated complexes.149–151,126 NHCs have been combined with transition metals from group 10 (i.e., Ni, Pd, and Pt) to develop rather active homogeneous catalysts for cross-coupling152, hydrosilylation8,124, cycloaddition153, and amination reactions154, to list a few. NHCs are a well-developed class of ancillary ligands in transition metal catalysts largely due to their modifiable steric and electronic properties that can tune the reactivity of the metal center. This modularity is achieved through the synthetically accessible substitution of the NHC backbone and of the N-moieties, making them great ligands to screen and construct catalyst structure-activity relationships. As both the steric and electronic components of NHCs can readily influence catalyst behavior, the evaluation of such parameters has been deeply studied. Specifically, the steric parameter of NHCs measures the total volume that the NHC occupies in the first coordination sphere of the metal is known as percent buried volume (%V 155,126Bur). One method to quantify the electronics of NHCs is through the Tolman electronic parameter (TEP).156 TEP was originally developed to assess phosphine electronics through simple substitutions on the phosphorous atom and has now been an adopted method to apply to NHC electron donating ability. 47 TEP values are achieved by measuring the CO stretch of the CO ligand trans to the NHC in (NHC)M(CO)x(X)y complexes by IR to relate the electron density in wavenumbers. 127 Both %VBur and TEP are powerful methods commonly applied to optimizing catalytic systems, and the information extracted from these systems can benefit future catalyst design. Within group 10 metals, (NHC)Ni catalysis has been of great interest largely due to the Earth-abundance and versatile reactivity of Ni. Outlined in Chapter II, our group has developed an (NHC)Ni(0)-catalyzed alkene hydrosilylation system for vinyl arenes and 2° and 3° silanes. The establishment of a homogeneous hydrosilylation catalyst inspired us to extract more information on the electronic structure of the (NHC)Ni(styrene)2 complexes and relate these findings to catalytic activity. In constructing a comprehensive understanding of the factors that influence stability, we also sought to understand the mechanism of the (NHC)Ni-catalyzed alkene hydrosilylation system. A few questions to address in this chapter are the following, 1) what affects catalyst stability? 2) what is the resting state of the catalyst? 3) how does NHC modification affect catalytic activity? This chapter describes the examination of electronic alteration of the pre- coordinated styrene through ligand exchange experiments and how it affects Ni catalyst stability and hydrosilylation reactivity. Additionally, initial mechanistic explorations of the (IMes)Ni(styrene)2 catalyst are presented here using 1H NMR resting state analysis. Lastly, a series of electronically and sterically altered NHC ligands were tested to understand what ligand properties assist in catalyst behavior, and the oxidation potential of these (NHC)Ni(styrene)2 complexes were probed using cyclic voltammetry (CV). 4.2 Results and Discussion Investigation of Electronic Influence on (IMes)Ni(0) Complexes After establishing the alkene substrate scope and observing the influence that electronically modified styrenes affect (IMes)Ni kinetics, we sought to investigate whether the resulting active catalyst formed was dependent on styrene identity. Therefore, to deconvolute the initial rates of reaction with possible ligand exchanges at Ni between the pre-coordinated styrene and free 4- substituted styrene substrate, we devised an experiment to further probe the styrene electronic contributions using styrenes 2c (OMe), 2f (F), and 2g (CF3). We measured the equilibrium 48 constants (Keq) of the ligand exchange reaction between 1e and styrene derivatives via 1H and 19F NMR spectroscopy (Figure 4.1.). Reacting complex 1e with 2.0 equiv of electronically varied styrenes (2c, 2f, 2g) in C7D8 at 75 °C for 4 h, a distribution of products consisting of the starting complex 1e, a monosubstituted 4-X-styrene complex (A), a disubstituted 4-X-styrene complex (B), uncoordinated styrene, and 3 2 1 0 -1 -2 -0.4 -0.2 0 0.2 0.4 0.6 σ Figure 4.1. Hammett plot for the ligand exchange between 1e and corresponding 4-X-styrene derivative (X = OMe, F, or CF3) to form a mixture of complexes A and B. Conditions: 1e (0.013 mmol, 1.0 equiv), 2c, 2f or 2g (2.0-2.1 equiv, 0.026-0.027 mmol), C7D8 (0.60 mL, 0.22 M), under N2. Concentrations of each species in solution was determined by integrations found in the 1H NMR spectra. uncoordinated styrene derivative was observed (Figure 4.1.). A Hammett plot was constructed employing the following derived equilibrium expression (See Appendix C, section C.1.5.a. for derivation): [𝐀][𝐁][styrene]3 Keq = (1) [4−X−styrene ]3[𝟏𝐞]2 A significant ρ value of +4.8 ± 0.4 was obtained, which reveals that ligand exchange from the bis- styrene complex 1e is more favorable with more electron-deficient vinylarene derivatives.135,136 49 log(Keq(X)/Keq(H)) Notably, this trend for alkene coordination, which is a thermodynamic measurement, is opposite to the trend for the rate of hydrosilylation, a kinetic effect. Taken together, the kinetic trend observed in hydrosilylation is influenced by the ground-state effect: rates with electron-rich alkenes are faster because the alkene-Ni complex is higher in energy. Mechanistically, these data imply that a ligand exchange process is occurring between precatalyst 1e and/or the resting state of the catalyst and the RDS. Catalyst Resting State and Decomposition Products To identify the resting state of the catalyst, we performed in operando studies using 1H NMR spectroscopy. We began with our simplest conditions: 2a, 3a, and 1e as the catalyst (10 mol % of 1e was used to facilitate observation of the Ni species present) reacting in C7D8 at 75 °C (Figure 4.2.). Conversion of 2a and 3a to product 4aa in 92% yield was observed. Notably, the selectivity of this reaction is moderate (l/b = 1:10), which is consistent with reactions at lowered temperatures (see Table A.2.). The only Ni species detected during the course of the reaction was complex 1e, demonstrating that 1e is the resting state of the catalyst when 2a and 3a are used. To observe the influence that styrene derivatives have on the resting state of the catalyst, analogous studies were carried out using 4-OMe-styrene (2c), 3a, and 1e as the catalyst. We questioned whether the resting state would be complex 1e or (IMes)Ni(4-OMe-styrene)2 (1h) because 1e is more stable than 1h (as demonstrated by the Hammett plot in Figure 4.1.), but there is a large excess of 2c relative to 1e, which would favor formation of 1h. The major Ni species observed during catalysis is indeed 1h, which reveals that the excess of 2c is sufficient to overcome the increased stability of 1e compared to 1h (Figure 4.2.). Because 1h is less stable than 1e and 1h is the major species formed and is therefore the resting state during catalysis, we can conclude that the ground-state stability of the catalyst resting state contributes to the increased rate of hydrosilylation with electron-rich alkenes. After reaction completion using 2a, 3a, and 1e as the catalyst, an emergent peak at -2.30 ppm assignable to a novel Ni dimer complex 1g was detected (Figure 4.3.). This complex was isolated and fully characterized by NMR spectroscopy as well as by single-crystal X-ray crystallography (see Appendix C, section C.1.3.). To test the competency of 1g as a catalyst, we subjected this Ni dimer to the hydrosilylation of 2a and 3a under standard reaction conditions. The hydrosilylation product 4aa was indeed obtained in 74% yield, albeit with regioselectivity favoring 50 Figure 4.2. 1H NMR monitoring of the hydrosilylation of 2c and 3a by 1e over time at 75 °C. Conditions: 2c (0.13 mmol, 1.0 equiv), 3a (0.14 mmol, 1.1 equiv), 1e (0.013 mmol, 10 mol %), C7D8 (0.6 mL, 0.22 M), under N2. Yield calculated using mesitylene as an internal standard. Bottom: spectroscopically observed Ni species in solution with the major species being 1h. the linear isomer (l/b = 1:0.9), which contrasts with that obtained when 1e is used as the catalyst (Table S1). Due to the divergent selectivity of 1g compared to 1e under identical reaction conditions in conjunction with observing the formation of 1g only at the end of the reaction, we attributed the formation of 1g to catalyst decomposition rather than catalyst activation. Stoichiometric studies between 1e and 3a were done to further understand the inclination of 1e to convert to 1g. Treating 1e with 2.0 equiv 3a in C7D8 yielded a mixture of 1g, 1e, and 4aa (1.0:1.4:2.0, respectively) within 5 minutes (see Appendix C). Therefore, we conclude that 1e is susceptible to degradation into 1g in the absence of excess alkene. To further confirm that 1e is not degrading during the reaction, “same excess” experiments from the Visual Kinetic Analysis approach to mechanistic studies was used (Figure 4.4.).157 Two reactions were performed side-by-side: reaction A used the standard conditions (0.22 M 2a, 0.24 M 3a, 0.011 M 1e), and reaction B used altered reaction conditions with decreased initial concentrations of reactants 2a and 3a (0.13 M 2a, 0.14 M 3a, 0.011 M 1e). After time adjustment, the reaction profiles ([4aa] versus time) overlay, indicating that the catalyst is not decomposing 51 (Figure 4.4.a.). Additionally, a third experiment, reaction C, used the same conditions as reaction B but with the Figure 4.3. 1H NMR monitoring of the hydrosilylation of 2a and 3a by 1e over time at 75 °C. Conditions: 2a (0.13 mmol, 1.0 equiv), 3a (0.14 mmol, 1.1 equiv), 1e (0.013 mmol, 10 mol %), C7D8 (0.6 mL, 0.22 M), under N2. Yield calculated using mesitylene as an internal standard. Bottom: proposed catalyst resting state (1e) and catalyst decomposition product (1g). addition of 4aa (0.087 mM) from the outset of the reaction. After time and [4aa] adjustment, the reaction profiles also overlay, suggesting that product 4aa does not inhibit catalysis (Figure 4.4.b.). Synthesis and Characterization of (ITMe)Ni(styrene)2 (1k) Once establishing the electronic influence that the pre-coordinated alkenes on (IMes)Ni(0)(alkene)2 complexes have on catalyst stability, we sought to construct a more in depth 52 understanding of how ancillary ligands affect catalytic behavior. Revisiting our ligand optimization results from Chapter II, ITMe was found to be the most promising ligand to yield the a 250 250 b c 200 200 150 150 100 100 kinetic profiles kinetic profiles overlay overlay A 50 A 50 B C 0 0 0 30 60 90 120 150 0 30 60 90 120 150 Time (min) Time (min) Figure 4.4. Visual Kinetic Analysis experiments: (a) reaction scheme, (b) time adjusted kinetic profile overlap of experiments A and B, (c) time adjusted kinetic profile overlap of experiments A and C. greatest amount of 4aa and best branched selectivity under unoptimized conditions performed at 70 °C (56% yield, l/b = 1:2) compared to IMes (21% yield, l/b = 1:1.5) and IPr (12% yield, l/b = 1:1.2) as the NHC (Figure 2.2. in Chapter II). Although, the characterization of a discreet (ITMe)Ni(styrene)2 species (1k) following similar synthetic protocols to obtain 1e proved confusing. A single crystal of 1k was isolated through slow THF/hexanes vapor diffusion but was unable to be fully characterized by single crystal XRD due to twinning effects. However, one out of two potential structures correspond to the bis-ligated styrene complex with both arenes on the styrene ligands facing downwards (Figure 4.5., left). Similarly, a previous report on the synthesis and structural analysis of a PtCl2(styrene)2 complex revealed the presence of multiple rotamers having varied styrene binding modes as determined by 1H and 195Pt NMR.158 1H NMR analysis of 1k displays a mixture of two distinct species, which are hypothesized to be rotamers shown in 53 [4aa] mM [4aa] mM Figure 4.5. (possible rotamers are shown on the left). To probe this, DOSY NMR was performed to unveil the number of species with different diffusion constants present in solution. DOSY NMR revealed that both species in solution have identical diffusion rates and are therefore likely identical in mass, supporting our hypothesis that 1k was isolated as a mixture of rotamers. Drawn in Figure 4.5., rotamer A is labelled as pink circles and these peaks correspond to 1k having symmetry down the z-axis. Rotamer B is labelled as a purple triangle and does not have symmetry along the same axis, as characterized by the four distinct peaks that correspond to each methyl group on ITMe (1.35, 1.45, 1.91, and 2.97 ppm). In further deconvoluting the mixture of rotamers, we performed variable temperature 1H NMR (VT NMR) on 1k was performed to see if 1k would coalesce into a single species at elevated temperatures. Monitoring changes in 1k by VT NMR over a temperature range (25 to 100 °C), the coordinated alkene peak at 2.73 ppm shifts upfield to about 2.61 ppm (hidden under methyl group in rotamer A). Additionally, in rotamer B, two methyl groups on ITMe (1.91 and 2.97 ppm) significantly shift downfield to 1.99 and 3.08 ppm relative to the other peaks in rotamer B. Whereas, peaks for rotamer A all shift downfield an equivalent amount. After heating 1k at 95 °C for 10 minutes, rotamer A and B did not coalesce, and remained as separate species in Figure 4.5. VT NMR spectra of 1k recorded in C6D6 at various temperatures (25-95 °C). 54 solution. The ratios of A and B slightly increased to favor A (from 1.2:1 to 2:1, A/B) throughout the heating process, however, the two remained relatively constant; therefore, we concluded that rotamers A and B are not in equilibrium with each other. Influence of (NHC)Ni(styrene)2 Catalyst Structure on Hydrosilylation Catalyst 1e was previously found to be the best performing hydrosilylation catalyst to react 2a with 3a to afford 4aa at 100 °C in toluene. Despite efforts to optimize the NHC ligand for alkene hydrosilylation, further exploration of the steric and electronics influence of the NHC on the Ni center is essential to enable advancements in (NHC)Ni-catalysis on a broader scale. Louie and coworkers have synthesized and characterized a library of electronically and sterically modifiable (NHC)Ni(styrene)2 complexes through simple alteration of the NHC backbone and/or N- moieties.126 Taking advantage of these complexes, we synthesized and prepared a series of sterically and electronically different (NHC)Ni(styrene)2 complexes (1e, 1k-1o) to test for alkene hydrosilylation (Figure 4.6.a.). Shown in Figure 4.6.a., the NHC ligands are ordered in ascending size from left to right as represented by the steric parameter, %VBur values, which were calculated using an (NHC)–M bond distance of 2.0 Å.129,126 The TEP values of each NHC evaluated are shown below the %VBur value for each NHC in Figure 4.6.a. and were determined by measuring the CO stretches of the CO ligand trans to the NHC ligand of interest on an [Ir] complex measured by IR127, apart from ITMe which was computationally derived128; a smaller wavenumber is equivalent to greater electron donation ability. To compare the reactivity of these complexes, we subjected 5 mol % of [Ni] for the hydrosilylation of 1.0 equiv 2a and 1.1 equiv 3a to yield 4aa at 80 °C in toluene (Figure 4.6.b.). In order to apply the method of initial rates, lower reaction temperatures (from 100 °C) were used to slow down the reaction enough to be able to accurately measure initial rates (Figure C.28., Table C.14.). 1k (ITMe) proved to be the fastest catalyst exhibiting 3.8x the rate compared to the parent complex 1e (IMes), followed by 1m (SIMes, 3.2x faster) and MeIMes (1n, 1.4x faster). The remaining two NHCs, 1l (ClIMes) and 1o (IPr), were 1.5x and 12x slower than 1e (IMes), respectively. At first glance, it appears that sterics may have the greatest influence on catalyst behavior with the fastest catalyst 1k bearing the smallest ligand (ITMe) and the slowest catalyst 1o having the largest ligand (IPr). However, the relationship between ligand sterics and catalyst kinetics fails to trend with the class of IMes-derivative NHCs (1e, 1l-1n), which may be due to the 55 100 80 (SIMes)Ni(styrene)2 (1m) (MeIMes)Ni(styrene)2 (1n) 60 (ITMe)Ni(styrene)2 (1k) (IMes)Ni(styrene)2 (1e) 40 (ClIMes)Ni(styrene)2 (1l) 20 (IPr)Ni(styrene)2 (1o) 0 0 30 60 90 120 150 180 Time (min) Figure 4.6. (a) Library of (NHC)Ni(styrene)2 complexes tested with the corresponding steric (%VBur) and electronic (TEP) parameters for each NHC. TEP, Tolman electronic parameter are measured in cm-1. (b) (NHC)Ni(styrene)2-catalyzed hydrosilylation monitored by GC using mesitylene or durene as an internal standard. Error bars are omitted for clarity. minimal change in sterics amongst these Mes ligands with only a Δ%VBur = 0.5. Taking a closer look at the TEP values of 1e and 1l-1n, no clear electronic trend is responsible for catalyst reactivity. This data suggests that neither the %VBur nor TEP forms of analysis to construct a catalyst structure-activity relationship are valid methods to parse out the factors responsible for (NHC)-catalyzed hydrosilylation activity. Beyond initial rates, we can analyze the full kinetic profile shown in Figure 4.6.b.. Despite 1k (ITMe) initially exhibiting the most rapid kinetics, it gradually levels out at 60% yield of 4aa 56 % Yield 4aa after 90 min and never reaches completion after 180 min, suggesting catalyst decomposition mid- reaction. Similarly, 1l (ClIMes) also decomposes by 150 min. The worst performing catalyst, 1o (IPr), is not a suitable catalyst for this transformation likely due to the excessive steric bulk of the IPr NHC ligand around the Ni center as previously discussed in Chapter II. Overall, 1m (SIMes) is significantly more reactive than the parent catalyst 1e (IMes), completing the reaction within 30 min while maintaining excellent branched selectivity of over 1:70 (l/b). This is a significant improvement in catalyst behavior to what is currently known for (NHC)-catalyzed alkene hydrosilylation. Following the best catalyst was found to be 1n (MeIMes), yielding 94% 4aa by 90 min and maintaining excellent selectivity (~1:50; l/b). These two ligands have similar steric parameters, but SIMes (1m) is slightly less electron donating than MeIMes (1n).159 These data infer the delicate interplay between sterics, electronics, and catalyst stability that contributes towards the structure-activity relationship of (NHC)Ni catalysts for alkene hydrosilylation. More ligand analysis and experimentation are required to conclude what major factors contribute to catalyst behavior. Electronic Characterization of (NHC)Ni(styrene)2 Complexes As previously shown, NHC ligand sterics and electronics are not adequate parameters to explain the reactivity of (NHC)Ni(styrene)2 complexes in alkene hydrosilylation. Therefore, we sought to explore the fundamentals of (NHC)Ni(styrene)2 complexes by relating the NHC identity in these complexes to the oxidation potential of (NHC)Ni(styrene)2 complexes. To investigate this, cyclic voltammetry (CV) studies of (NHC)Ni(styrene)2 complexes (1e, 1k, 1m-1o) bearing varied NHC structures were collected in an electrolyte solution of 0.01 M [NBu4][ClO4] in DMF at 100 mV•s-1. Scanning oxidatively, 1e, 1k, 1m-1o all display two oxidative peaks corresponding to Ni0/NiI and NiI/NiII, while no reversible redox features were observed (Figure 4.7., left). Attempts to scan reductively to observe reversible redox features were unsuccessful. The complexes that most readily oxidized (Ni0/NiI) were found to be 1n (MeIMes) and 1k (ITMe) with oxidative features appearing at -0.73 V (all potentials are calibrated vs Fc+/Fc) and -0.72 V, respectively, followed by 1m (SIMes) at -0.64 V, 1e (IMes) at -0.62 V, and lastly 1o (IPr) at -0.47 V (Figure 4.7., right). Complexes that were more readily oxidized trended well with the rates of hydrosilylation with the exception of 1m (SIMes). Namely, 1k (ITMe) and 1n (MeIMes) have the highest oxidation potential and exhibit faster kinetics while 1o (IPr) had the lowest oxidation 57 Ni0/NiI NiI/NiII complex (V) (V) 1n -0.73 0.51 (MeIMes) 1k -0.72 0.56 (ITMe) 1m -0.64 0.57 (SIMes) 1e -0.62 0.51 (IMes) 1o -0.47 0.55 (IPr) Figure 4.7. Left: CV data for complexes 1e, 1k, 1m, 1n, and 1o. Right: Ni complex of interest, the voltage corresponding to the first oxidation (Ni0/NiI) followed by the second oxidation (NiI/NiII). potential of -0.47 V and was also the slowest to catalyze hydrosilylation. All complexes displayed an oxidation peak that corresponds to NiI/NiII with similar oxidation potentials ranging from 0.51- 0.57 V. Although the CVs of these complexes are unable to fully elucidate the trends observed for hydrosilylation of (NHC)Ni complexes, it does provide insight into how the NHC influences the Ni complex oxidation potential. This method has the potential to be used as a metric for NHC–Ni bond strength or even Ni stability for both current and future studies for these types of complexes. 3.3 Conclusion In summary, the work in Chapter IV describes the assessment of the electronic structure of the (NHC)Ni(alkene)2 complexes using both NMR and CV techniques and its mechanistic implications in alkene hydrosilylation. Building upon Chapter II and III, a deeper understanding on the influence of the styrene and NHC ligands in (NHC)Ni(styrene)2-catalyzed alkene hydrosilylation has been developed. In short, styrene ligands that possess stronger electron withdrawing ability are more stable than their electron donating counterparts. Thus, more efficient catalyst activation is achieved with more electron rich styrenes while simultaneously destabilizing the Ni center. To provide insight on catalyst behavior, an in operando 1H NMR catalyst resting state experiment was performed. Mechanistically, we can attribute the starting (IMes)Ni(styrene)2 58 (1e) complex as the resting state, indicating that the pre-catalyst reformation is highly reversible. Next, the synthesis and analysis of (ITMe)Ni(styrene)2 (1k) was achieved using multiple NMR spectroscopy methods to discern the mixture of species, which are predicted to be two distinct rotamers. After identifying the speciation of 1k (ITMe), this complex along with other (NHC)Ni(styrene)2 derivatives (1e, 1l-1o) were tested as catalysts for alkene hydrosilylation to evaluate NHC impact on catalytic behavior. SIMes was found to be the best NHC for this transformation, which did not trend with either NHC electronics or sterics when applying the %VBur and TEP parameters, respectively. This result led us to explore a new avenue to probe the electronic structures of 1e, 1k, 1m-1o by CV. Both 1n (MeIMes) and 1k (ITMe) exhibited the highest oxidation potential of -0.73 V and -0.72 V (vs. Fc+/Fc), respectively, while the bulkiest complex, 1o (IPr), displayed the lowest oxidation potential of -0.47 V. Overall, new methods have been presented in Chapter IV to assess the electronic structure and stability of (NHC)Ni(alkene)2 complexes have been developed using 1H NMR ligand exchange and CV experiments. However, attempts to rationalize 1m (SIMes) exhibiting the best catalytic reactivity remains unsuccessful. Future work can be done to further explore this phenomenon such as performing more in depth CV analysis using varied (IMes)Ni(alkene) complexes with chelating alkene ligands to increase Ni(0) stability. Additionally, density functional theory can be applied to predict the mechanism of (NHC)Ni-catalyzed hydrosilylation as well as the relative stability that each NHC provides. The assessment of using different NHC ligands described in Chapter IV can potentially be applied to remote hydrosilylation systems. Knowing the relative rates that each NHC induces on the (NHC)Ni(styrene)2 complexes, we can control the desired rate of reaction relative to isomerization to install a silicon group distal to the original reactive site. More details on this chemistry are further discussed in chapter V. 59 CHAPTER V DEVELOPMENT OF A HOMOGENEOUS (NHC)Ni(0)-CATALYZED REMOTE HYDROSILYLATION SYSTEM The work in Chapter V was developed by Alison Sy-min Chang and Professor Amanda K. Cook and the synthetic and catalytic system development was carried out by Cailey Carpenter, Gaby Bailey, and Alison Sy-min Chang. 5.1 Introduction Alkene hydrosilylation is an industrially relevant reaction that adds a H–Si bond across a double bond, yielding precursors for silicone materials that are utilized in our daily lives.29 Unsustainable Pt catalysts are currently used for this transformation, and are typically limited to the formation of just one product, the linear isomer.13,30,42 Formation of the branched isomer has been substantially less developed.116,117 The branched isomers are highly valuable, since they are used in specialty applications like silicone coatings and adhesion promoters.27,28 Furthermore, selective conversion of a long chain alkene to afford a branched organosilicon product remains elusive. This transition metal-catalyzed reaction, known as remote hydrosilylation (RHS), is an efficient method to obtain organosilicon products that originate from an alkene distal to the initial reaction site (Figure 5.1.a.). This reactivity is achieved through alkene isomerization along a long alkyl chain followed by functionalization to yield high-value organosilicon products. As with standard hydrosilylation, known precious160–165 and base metal166,88,49,66,167,68,168,169 catalysts perform RHS to form the linear product, thus highlighting the significant unmet challenge in obtaining branched products through this method. To our knowledge, only one example by Zhu and coworkers displays this reactivity using a (phenanthroline)Fe catalyst, but there are limitations to this work, including a lack of substrate scope and only moderate selectivity for the branched product (b/l = 9.0:1, Figure 5.1.b.).102 The potential to contribute to the field motivated us to develop a modular, branched-selective RHS system. 60 Figure 5.1. (a) Remote hydrosilylation of a terminal alkene and a 3° silane catalyzed by a transition metal complex. (b) Example of a branched-selective remote hydrosilyation catalyst in the literature. (c) This work on remote hydrosilylation utilizing (NHC)Ni cataylsts. As described in Chapters II-IV, we have developed a (NHC)Ni (NHC = N-heterocyclic carbene) catalytic system that readily activates 2° and 3° silanes for alkene hydrosilylation to from the branched product.170 Other work in our group has led to the development of a tunable homogeneous (NHC)Ni/HSiPh3 alkene isomerization system. 6 Thorough mechanistic investigations of each (NHC)Ni-catalyzed hydrosilylation and isomerization systems were performed, separately, to reveal that each reaction is likely facilitated by a Ni–H species. Furthermore, NHC ligand screening was found to impact catalyst activity. Taking advantage of our previously gained mechanistic understanding of these catalytic processes, we sought to develop a dual catalyst system based on (NHC)Ni complexes composed of Earth-abundant elements for RHS of long-chain alkenes to install a silicon group at the benzylic position.6,170 This is achieved by using a large (NHC)Ni catalyst for alkene isomerization, and a small (NHC)Ni catalyst for hydrosilylation (Figure 5.1.c.). In developing an accessible dual catalytic system, we have strategized to generate the active Ni catalysts in situ using a Ni(0) precursor and corresponding ligands. This approach removes many synthetic steps required to synthesize the catalyst and it allows for rapid evaluation of ligand combinations, facilitating reaction optimization. 61 5.2 Results and Discussion Alkene Isomerization The first step in RHS is alkene isomerization followed by the second step, alkene hydrosilylation. Therefore, the rate of isomerization from a terminal alkene to an internal alkene must be greater than the rate of hydrosilylation. Kawamura et al. showed an NHC ligand size dependence on catalyst activity such that a larger NHC (IPr) yielded more isomerized product. Following this trend, we hypothesized that a larger IPr NHC would facilitate alkene isomerization more efficiently. We initiated our optimization by screening three sterically diverse IPr (IPr = 1,3- bis(2,6-diisopropylphenyl)imidazol-2-ylidene) derivatives for the isomerization of allylbenzene (1a, Figure 5.2.). The steric bulk of the three IPr NHCs evaluated for this reaction are determined by %VBur and are listed in ascending steric bulk 126: IPr (38.5), ClIPr (39.1), and MeIPr (39.6). The isomerization of 1a to 2a was facilitated by 5 mol % Ni(COD)2 (COD = 1,5-cyclooctadiene), IPr NHC, and HSiPh3 at 60 °C in toluene and monitored by GC (Scheme 5.1.). As expected, the largest NHC, MeIPr, exhibited the fastest kinetics and completed isomerization within 44 min. Following MeIPr is IPr, converting 46% 1a to 2a within 5 h and the slowest NHC was ClIPr, only reaching 6% conversion to 2a. These results indicate that sterics are not the main contributing factor to catalyst activity, encouraging us to evaluate the NHCs as a function of σ-donating strength measured in Tolman electronic parameter (TEP); smaller TEP values correlate to stronger σ- donating strength. Indeed, the stronger NHC σ-donation correlated to faster isomerization rates: MeIPr is the most electron donating followed by IPr and then ClIPr. With MeIPr as the best ligand for alkene isomerization, we continued optimization using a longer chain alkene, 4-Ph-1-butene (1b), as our model substrate. We next evaluated the Ni(0) source and envisioned that an air-tolerant Ni(0) precatalyst would increase catalyst stability throughout the reaction. Therefore, we tested Ni(COD)2 and Ni(COD)(DQ) (DQ = duroquinone), an air-tolerant Ni(0) source. DQ has been reported to stabilize Ni by adopting various binding modes to Ni in Ni(COD)(DQ)-catalyzed reactions.171 Using MeIPr as the NHC source, the isomerization of 1b to A-2b and B-2b was tested using Ni(COD)2 and Ni(COD)(DQ) at 40 °C in toluene (Scheme 5.2.). As the goal of this RHS system is to install a silicon group on the most 62 100 IPr 80 ClIPr 60 MeIPr 40 20 0 0 1 2 Time (h) 3 4 5 Scheme 5.1. NHC screen for the isomerization of 1a to 2a by Ni(COD)2/NHC/HSiPh3. NHC, N- heterocyclic carbene; COD, 1,5-cyclooctadiene; dipp, diisopropylphenyl; %VBur, % buried volume; TEP, Tolman electronic parameter. Conditions: Ni(COD)2 (0.0091 mmol, 5 mol %), NHC (0.0091 mmol, 5 mol %), HSiPh3 (0.0091 mmol, 5 mol %), 1a (0.18 mmol, 1.0 equiv), toluene (1.1 mL, 0.16 M), 60 °C. Yields are determined by calibrated GC analysis using durene as an internal standard. internal position of the alkyl chain, we are targeting the formation of B-2b due to benzylic functionalization accessibility. In order to achieve this site selectivity, the Ni catalyst must chain- walk, the sequential movement of a double bond along an alkyl chain, across two carbons to obtain the desired product, B-2b (Scheme 5.2., top). To accurately observe this reactivity, a decreased reaction temperature was used to assess the rate of B-2b formation over time. An induction period of 1 h was observed with Ni(COD)2, and the formation of B-2b (gray triangles) did not initiate until 71% A-2b (orange squares) was formed (Scheme 5.2., bottom left). Approximately 77% B- 2b formed by 6 h. No induction period was observed using Ni(COD)(DQ), and 98% of 1b was fully converted to form 46% A-2b and 52% B-2b (Scheme 5.2., bottom right). The gradual formation of B-2b led to a similar total conversion of 75% in comparison to using Ni(COD)2 (77% B-2b) within 6 h. Due to the presence of the induction period using Ni(COD)2 as the precatalyst, we chose to use Ni(COD)(DQ) as the Ni(0) source moving forward. 63 % Conversion to 2a 100 100 1b A-2b B-2b 1b A-2b B-2b 80 80 60 60 40 40 20 20 0 0 0 1 2 3 4 5 6 0 1 2 3 4 5 6 Time (h) Time (h) Scheme 5.2. Evaluation of Ni(0) precatalysts for the isomerization of 2a to A-2a and B-2a. Conditions: [Ni] (0.0060 mmol, 5 mol %), MeIPr (0.0060 mmol, 5 mol %), HSiPh3 (0.0060 mmol, 5 mol %), 1a (0.12 mmol, 1.0 equiv), toluene (0.5 mL, 0.24 M), 40 °C. Yields are determined by calibrated GC-MS analysis using mesitylene as an internal standard. Alkene Hydrosilylation Described in Chapter IV, NHC optimization for (NHC)Ni-catalyzed alkene hydrosilylation of styrene and diphenylsilane led to SIMes as the best performing ligand, completing the reaction within 30 min at 80 °C (see Figure 3.4. for details). Considering the desired relative rates of reaction for RHS, faster isomerization in comparison to hydrosilylation is desired. Therefore, we moved forward using the second-best ligand for hydrosilylation, MeIMes, to optimize for the RHS and 1b and 3a using the optimal Ni(0) source found for alkene isomerization, Ni(COD)(DQ). Reacting 1b and 3a by 5 mol % MeIPr, 5 mol % MeIMes, and 10 mol % Ni(COD)(DQ) at 80 °C in toluene for 24 h, 75% conversion of alkene to RHS product was achieved with a 0.9:1 (4a/4b- 4d) selectivity of the desired hydrosilylation product (entry 1, Table D.7.). The product selectivity was rather low, suggesting that alkene hydrosilylation was too fast relative to isomerization. To slow down the rate of hydrosilylation, we proceeded in testing the RHS of 1b and 3a using IMes 64 % Conversion % Conversion instead of MeIMes. Indeed, product selectivity increased to 1.9:1 (4a/4b-4d) with only 53% of the alkene converted to RHS product (entry 2, Table D.7.). With variations in RHS product selectivity, we revisited our previously established optimal conditions for (NHC)Ni-catalyzed alkene hydrosilylation of styrene and a 3° silane discussed in Chapter II. ITMe was found to be the most compatible ligand at 100 °C due to smaller steric bulk. Therefore, we continued our optimizations using ITMe as the hydrosilylation ligand. To achieve good 4a selectivity, we redirected the optimization to solely focus on the hydrosilylation of B-2b and 3a by modifying the reaction solvent. As (NHC)Ni-catalyzed alkene hydrosilylation was more efficient in less polar solvents, we tested four non-polar solvents at 100 °C (Table 5.1.). Toluene was the worst performing solvent in terms of both yield (32%) and selectivity of 4a (10:1, 4a/4b- 4c; entry 1) followed by n-octane (entry 3, 43% yield; 13:1, 4a/4b-4c; Table 5.2.). Both cyclohexane (entry 2) and hexanes (entry 4) were both selective for 4a (20:1 and 32:1, respectively; Table 5.1.), we proceeded optimization using cyclohexane because it was consistently higher yielding of 41%. Remote Hydrosilylation After establishing the optimal NHC ligands for both alkene isomerization and alkene hydrosilylation, separately, we tested RHS at various temperature regimes. Shown in Figures 5.2. and 5.3., alkene isomerization readily proceeds at lower temperatures (40 and 60 °C), however, hydrosilylation requires an elevated reaction temperature (100 °C) as described in Chapter II. Therefore, we envision that the formation of 4a from 1b and 3a can be kinetically obtained by Table 5.1. Solvent screen for the hydrosilylation of B-2b and 3a by ITMe/Ni(COD)(DQ). Dielectric Selectivity Entry Solvent % Yield 4a Constant (4a/4b-4d) 1 Toluene 2.38 32 10:1 2 Cyclohexane 2.02 41 20:1 3 n-octane 1.95 43 13:1 4 Hexanes 1.89 29 32:1 % Yield determined by 1H NMR using trimethoxybenzene as an internal standard. Selectivity determined by GC-MS. 65 promoting alkene isomerization to afford B-2b while inhibiting hydrosilylation at a lower reaction temperature followed by increasing the reaction temperature to 100 °C for alkene hydrosilylation. The RHS of 1.0 equiv 1b and 1.0 equiv 3a by 1:1 ITMe/MeIPr and 10 mol % Ni(COD)2 was conducted in toluene at 50 °C while monitoring isomerization by GC. Ni(COD)2 and toluene were chosen for solubility at lower temperatures. After 8.5 h at 50 °C, 86% of 1b was converted to 25% A-2b and 75% B-2b and increasing the reaction temperature to 100 °C for 24 h converted 64% alkene to yield 3.1:1 4a/4b-4d (entry 1, Table D.8.). We hypothesized that the low 4a-selectivity was a result of incomplete isomerization, therefore by increasing the isomerization temperature to 60 °C for 7 h, 16% A-2b and 84% B-2b was obtained followed by 68% of alkene converted to product and resulted in a higher ratio of 4.2:1 4a/4b-4d after stirring the reaction at 100 °C for an additional 24 h (entry 2, Table D.8.). As isomerization ran for ~8 h prior to activating the hydrosilylation catalyst, we wondered if the hydrosilylation catalyst was decomposing while stirring in solution. Therefore, we tested the RHS of 1.0 equiv 1b and 1.0 equiv 3a by 1:1 MeIPr/ITMe (5 mol % of each NHC was used) and 10 mol % Ni(COD)(DQ) in cyclohexane at 100 °C for 21 h. 78% of 1b was consumed to form 4a and 4b with a selectivity of 5.0:1 (4a/4b, entry 3, Table D.9.). Within the same reaction, 0% of 3a and 20% of unreacted B-2b remained, respectively, along with 5% hydrogenated 1b, an undesirable byproduct of this reaction. The presence of unreacted B-2b implies that isomerization was faster than hydrosilylation before the hydrosilylation catalyst decomposed. To encourage hydrosilylation, we increased the MeIPr/ITMe ratio to 1:3 while maintaining 10 mol % Ni(COD)(DQ), however no improvement in reactivity was observed (entry 4, Table D.9.). With minimal amounts of 3a remaining coupled with the formation of hydrogenated 1b, this competing side reaction between 3a and 1b complicates desired catalytic activity. We hypothesized that a method to inhibit this side reactivity could be achieved by lowering the reaction temperature to 90 °C. Using standard conditions at 90 °C for 24 h, 93% alkene was consumed and a selectivity of 10:1 4a/4b-4d was achieved with only 3% B-2b remaining; albeit with a greater amount of hydrogenated 1b forming (13%). Overall, these preliminary results showcase the potential in further optimizing the RHS of 2a and 3a to obtain 4a in high yield and selectivity >10:1 (4a/4b- 4d). 66 5.3 Conclusion RHS, the isomerization of an alkene to a position distal to the initial reaction site followed by hydrosilylation of the newly formed alkene, is a powerful method to obtain high value branched organosilicon products. Chapter V describes our motivation to devise a dual catalytic system by combining and simplifying our previously established (NHC)Ni-catalyzed alkene isomerization and hydrosilylation systems to increase reaction efficiency and decrease chemical waste from sequential work ups. Building upon work done by Dr. Kawamura et al6, we show that a thorough investigation in modifying the stereoelectronics of the IPr ligand for isomerization was successful– MeIPr, the strongest NHC σ-donor, proved to be the best candidate. Once identifying MeIPr as the ligand of choice for alkene isomerization, we next evaluated optimal conditions for hydrosilylation and found that ITMe paired with Ni(COD)(DQ) was the best performing system, which is consistent with results discussed in Chapter II. Cyclohexane was also found to be the best solvent environment to mediate hydrosilylation. Lastly, the combination of these two systems led to further optimization through temperature variations to acquire kinetic control over the desired product selectivity. We show that optimization via hypothesis-driven rationale such as modifying the ligand, solvent environment, and reaction temperature has the potential to yield the branched product (4a) in high yield and selectivity. The foundational establishment of this RHS system has contributed to further understanding the relative rates of each reaction. Additionally, the work described in Chapter V can inform future (NHC)Ni catalytic systems, of which a detailed understanding of ligand electronics on isomerization and ligand sterics on hydrosilylation is presented and shows that Ni reactivity is indeed deeply affected. 67 CHAPTER VI DEVELOPMENT OF A HETEROGENEOUS NICKEL–HYDRIDE CATALYST FOR ALKENE ISOMERIZATION This chapter includes unpublished work done by Alison Sy-min Chang as well as submitted and co-authored material from Chang, A. S.; Kascoutas, M. A.; Valentine, Q. P.; How, K. I.; Thomas, R. M.; Cook, A. K. Alkene Isomerization using a Heterogeneous Nickel–Hydride Catalyst. Submitted. 10.26434/chemrxiv-2023-rt2gt. This article was written by Alison Sy-min Chang, with editorial assistance from Melanie A. Kascoutas and Professor Amanda K. Cook. Melanie A. Kascoutas and Kiera I. How contributed synthetically through the preparation of starting materials. Quinn P. Valentine and Rachel M. Thomas performed preliminary work to establish the project. 6.1 Introduction Transition metal-catalyzed alkene isomerization is an appealing approach to reposition an alkene within a molecule (Figure 6.1.a.).172,173 Significant advancements in the field of homogeneously catalyzed isomerization have been made,174–176 but efficient and selective heterogeneous catalysts for isomerization remain sparse, despite the potential to apply the advantages of heterogeneous catalysis (recyclability, added stability, complementary selectivity).177,178 Currently, this area of catalysis is severely underdeveloped and dominated by the use of precious metals, specialty organic polymers as supports, and ill-defined active sites in nanoparticles. Notable examples of single-site catalysts include works by Ley,179 Grotjahn,180 and Jia181 which immobilize Ir, Ru, or Rh complexes, respectively, onto ligand-modified organic polymers (Figure 6.1.b.). These systems display good catalyst recyclability, but at the expense of reduced catalytic activity and/or E/Z-selectivity in comparison to their homogeneous analogues. Many nanoparticle-based catalysts for alkene isomerization are known, but because of their crude synthesis methods (e.g., treatment under hydrogen at elevated temperatures), the active sites are unknown, making structure-activity relationships challenging to elucidate (Figure 6.1.b., top right).182,183 Likely because of this lack of control in the synthesis, the activity and selectivity of the catalysts tend to be low. Because the structure of single-site catalysts can be designed and 68 systematically modified, they have the potential to control, understand, and improve reactivity.178,184 Figure 6.1. (a) Alkene isomerization. (b) Types of heterogeneous catalysts for alkene isomerization. (c) Ni/H2SO4 generation and decomposition. (d) This work: development of Ni/SZO300 for alkene isomerization. A pivot towards more precise methods to prepare heterogeneous catalysts bearing well- defined active sites grants the ability to develop structure–activity relationships and encourages further catalyst development. Strategies to synthesize single-site catalysts include the surface organometallic chemistry (SOMC) approach185 and the use of metal-organic and covalent organic frameworks (MOFs and COFs, respectively), and both have had limited success with alkene isomerization. Estes demonstrated that an alumina-supported platinum-hydride is effective at 1- hexene isomerization (Figure 6.1.c., bottom right),186 and a handful of examples of MOFs show activity for 1-butene isomerization and E/Z isomerization.187–189 While these advancements demonstrate the potential of single-site catalysts in alkene isomerization, their substrate scopes are highly limited and often utilize precious metals as the active site. SOMC is an evolving method that reaps the benefits of both homogeneous and heterogeneous catalysts. Typically, catalysts prepared using a SOMC approach deliver reactive 69 species with molecular precision and enhanced stability compared to their homogeneous analogs. Select examples show marked catalytic improvement over their homogeneous analogs (e.g., [W]/SiO2–catalyzed alkene metathesis, 190 [Ir]/SiO2–catalyzed methane borylation, 191 and [Hf]/sulfated zirconia-catalyzed ethylene/1-octene copolymerization),192 demonstrating the potential of this approach. Cramer and Lindsey found that Ni(0) in combination with sulfuric acid generates a highly active catalyst for alkene isomerization,193 and Tolman studied the reaction’s mechanism and the structure of the active catalyst.194,195 A cationic Ni–H is proposed as the active catalyst, which forms from protonation of the Ni(0) center with the strong acid. This catalyst, while highly active, decomposes rapidly by a second equivalent of H+, irreversibly forming an inactive Ni(II) species and H2 (Figure 6.1.c.). We hypothesized that immobilization of the [Ni–H] + catalyst would prevent this decomposition, thereby improving catalyst stability and broadening its use in organic synthesis. Efforts to improve this catalyst’s stability by means of heterogenization were performed using sulfated polymers;196,197 this strategy improved the catalyst stability and recyclability, but at the expense of catalytic activity and alkene selectivity compared to the homogeneous catalyst (vide infra). Using acidic metal oxides offers significant advantages over polymer-based supports, including ease and precision of synthesis and cost of materials.198,199 Because of these advantages, the SOMC approach using acidic metal oxides has been taken to generate active catalysts for a wide variety of applications, such as hydrogenation,200,201 ethylene (co)polymerization,202,203,192 H/D exchange,204,205 hydrogenolysis,206 and alkane metathesis.206 These active sites are generated by protonolysis or abstraction of an X-type ligand at the metal center. We hypothesized that the novel strategy of protonating metal centers with these strongly acidic metal oxides would be effective in generating immobilized [M–H]+ species, which are broadly invoked as active sites in catalysis. Due to its straightforward nature, this SOMC approach also has the potential to inform future catalyst design and rationale for analogous systems. This strategy would be particularly useful in addressing the challenge of the decomposing [Ni–H]+ catalyst for alkene isomerization. In this report, we demonstrate that our novel approach is successful: the acidic metal oxide, sulfated zirconia (SZO300) is an excellent proton source and support for generating a putative [Ni– H]+ active site, which is highly active and selective catalysts for alkene isomerization (Figure 6.1.d.). We demonstrate that the catalyst, Ni/SZO300, is compatible with a broad scope of alkenes 70 including those containing functional groups with heteroatoms, halides, acid-labile groups, and electronically and sterically diverse groups. Recyclability and catalyst aging studies reveal enhanced catalyst stability. Notably, this heterogeneous catalyst shows marked improvements in stability, selectivity, and functional group tolerance in comparison to the homogeneous analog. Lastly, we show the versatility of this heterogeneous [Ni–H]+ catalyst and have successfully applied it to various alkene hydrofunctionalization reactions. 6.2. Results and Discussion Optimization We initiated our investigations using metal oxides as potential acid sources to generate [Ni–H]+ species from protonation of Ni[P(OEt)3]4. We speculated that [Ni–H] + active sites could be formed by reacting this Ni0 complex with isolated surface hydroxyls. A series of metal-oxide supports commonly used in SOMC, silica dehydroxylated at 700 °C (SiO2-700), alumina dehydroxylated at 700 °C (Al2O3-700), and zirconia dehydroxylated at 700 °C (ZrO 185,198 2-700), were screened for the isomerization of 4-allylanisole (1a) to anethole (2a), but all failed to demonstrate any desired reactivity (Table 6.1., entries 1-3). We postulated that the surface hydroxyls were not acidic enough to favorably generate the [Ni–H]+ active species, so we tested a more acidic metal oxide, sulfated zirconia (SZO ).199,207300 Isomerization of 1a proceeded to a good yield and selectivity of 2a with SZO300 (78% yield 2a, E/Z = 17:1; Table 6.1., entry 4). The major isomer is the E-isomer, which is more thermodynamically stable than the Z-isomer. The reaction proceeds easily at room temperature, but we chose to run most reactions at 30 °C to ensure consistent temperature control. We proceeded with SZO300 as the acid source for 1a isomerization. No yield of 2a or conversion of 1a was observed under these conditions when nickel or SZO300 was excluded from the reaction (Table E.2.). As a direct comparison to the homogeneous catalyst, the isomerization of 1a to 2a using H2SO4 as the acid source provided 2a in higher yield (86%; Table 1, entry 5) than when SZO300 was used (78%; Table 1, entry 4), but the E/Z selectivity was comparable (E/Z = 17:1 for both H2SO4 and SZO300). Additional Ni 0 sources were also evaluated, and all gave low yields of product (<5%; Table S2). The catalyst loadings of Ni[P(OEt)3]4 and SZO300 were optimized to 3 and 5 mol %, respectively, and Et2O remained the optimal solvent (Table E.2.). Under these conditions, 1a 71 is isomerized to 2a in 1 h in high yield (83%) and high selectivity (E/Z = 22:1; Table 6.1., entry 6), exhibiting a similar yield to that of using 3 mol % of H2SO4 (86%), but with better E-selectivity Table 6.1. Evaluation of acid sources for the isomerization of 1a to 2a. Entry Acid Source (mol %) Yield Selectivity (E/Z) 1 SiO2-700 (3) 0% n.d. a 2 Al2O3-700 (3) 0% n.d. 3 ZrO2-700 (3) 0% n.d. 4 SZO300 (3) 78% 17:1 5 H2SO4 (3) 86% 17:1 6 SZO300 (5) 83% 22:1 7b H2SO4 (5) 63% 11:1 8 NafionTM (5) 10% 15:1 9 Amberlyst®-15 (5) 20% 11:1 Conditions: 1a (0.060 mmol, 1.0 equiv), Ni[P(OEt)3]4 (0.0018 mmol, 3.0 mol %), Et2O (1.0 mL). Yields and selectivities determined by gas chromatography (GC) analysis using cyclooctane as an internal standard. an.d., not determined. b1a (0.12 mmol, 1.0 equiv), Ni[P(OEt)3]4 (0.0060 mmol, 5.0 mol %), Et2O (2.0 mL). (E/Z =17:1 for H2SO4). Increasing H2SO4 loading to 5 mol % gave a lower yield of 2a (63%) with poor selectivity (E/Z = 11:1; Table 6.1., entry 7), suggesting that the active Ni catalyst may be decomposing in the presence of this slight excess H2SO4, as previously reported. 194,195 NafionTM and Amberlyst®-15 are both acidic organic polymers and have been used as supports in heterogeneous catalysis.196,197,208 Evaluating these materials in place of SZO300 under our conditions revealed that they are not as effective as SZO300. Nafion TM was the worst- performing acid, yielding 10% 2a (E/Z = 15:1; Table 6.1., entry 8), and Amberlyst®-15 gave slightly higher yield (20% yield; E/Z = 11:1; Table 6.1., entry 9). The reactions using three acidic supports (SZO300, Nafion TM, and Amberlyst®-15) and H2SO4 were studied more deeply by analyzing the reaction progress over time. The plot of the yield of 2c over time using the three solid acids shows linear formation of the product from 0-45 min (Figure 6.2.a.). The slopes of these linear portions were calculated, and comparing these slopes shows that the Ni/SZO300 catalyst is 4 and 10 times faster than the Ni/Amberlyst®-15 and Ni/NafionTM catalysts, respectively (Figure E.12.). 72 Catalyst Characterization To unveil the amount of Ni that grafts onto SZO300, a reaction between 3:5 [Ni]/SZO was performed. This organometallic complex was prepared by gently stirring a reaction of 0.0187 mmol Ni[P(OEt)3]4 and 0.0300 H + mmol SZO300 in Et2O for 1.5 h at 23 °C. A stark color change from white (SZO300) to bright orange (grafted material, [Ni]-SZO) was immediately observed upon introducing the colorless solution of Ni[P(OEt)3]4 to SZO300, visually indicating that a reaction on the surface had occurred (Figure 6.1.d., bottom right). The reaction filtrate was analyzed by 31P{1H} NMR in C6D6 against tetraethyl ethylenediphosphonate as an internal standard. Approximately 73% of Ni[P(OEt)3]4 successfully grafted onto SZO300 using 3:5 [Ni]-SZO (see Appendix E for details). Upon isolation, the surface organometallic complex, [Ni]-SZO (6.08 wt % Ni by ICP-MS), was characterized by solid state NMR spectroscopy. As expected, the 1H MAS NMR spectrum showcases signals corresponding to coordinated P(OEt)3 at 4.09 and 1.28 ppm. Two additional signals further upfield show characteristic hydride resonances at -12.10 and -14.21 ppm, indicating that Ni[P(OEt)3]4 is indeed protonated by SZO300. The appearance of two hydride signals could correspond to the corresponding [Ni–H]+ species: HNi[P(OEt)3]4 and HNi[P(OEt)3]3, which were previously observed in the homogeneous analog using H2SO4 as the acid source. 194 Additionally, other late transition metal-hydride complexes prepared via SOMC are commonly found within this region.209,173 The IR spectrum of [Ni]-SZO further corroborates the presence of a Ni–H in the grafted material as indicated by a weak band at 1935 cm-1.210,211 This data is consistent with previously reported [Ni–H]+ complexes. The 13C MAS NMR spectrum of [Ni]-SZO exhibits two peaks at 61.8 and 15.5 ppm that also corresponds to the coordinated P(OEt)3 ligands. Lastly, a single resonance at 134.28 ppm was observed in the 31P MAS NMR spectrum, which is significantly upfield compared to Ni[P(OEt)3]4 taken in C6D6 (159.23 ppm). This change in chemical shift is expected to correspond to a loss in electron density at the Ni center after protonation to form cationic [Ni–H]+ complexes, as similar homogeneous cationic NiII species are found within this region.212 Overall, these data point towards the likelihood of Ni[P(OEt)3]4 protonation by SZO300 to form [Ni–H] + species on the surface. 73 Catalyst Heterogeneity, Stability, Robustness, and Practicality To investigate the heterogeneity of Ni/SZO300, a hot-filtration test was conducted using grafted [Ni]-SZO that was previously prepared. Using standard reaction conditions, two experiments with 1a were run in parallel and the reaction progress was monitored over time (Figure 6.2.b.). The standard conditions and procedure were used for one reaction (Figure 6.2.b., green diamonds); the other reaction was filtered while at 23 °C after 20 minutes and the reaction progress of the filtrate was continued to be monitored (Figure 6.2.b., yellow triangles). Heterogeneously catalyzed isomerization will cease after filtration, and if the active catalyst is leaching from the surface to form a homogeneous catalyst in situ, the concentration of product will keep increasing. ICP-MS analysis of the filtered reaction filtrate resulted in 5% of Ni leaching from the solid catalyst, which is likely due to the solid catalyst breaking down by the stir bar, thereby releasing Ni into solution. However, as anticipated, the filtered reaction stagnated, with no additional conversion of 1a, formation of 2a, or change in the E/Z ratio. This key finding supports the notion that this catalyst is heterogeneous in nature. 100 100 80 80 60 60 40 40 20 20 filtered 0 0 0 30 60 90 120 150 180 0 30 60 90 120 Time (min) Time (min) H22 SO44 SZO300 Amberlyst-15 Naffiion not filtered filtered Figure 6.2. (a) Comparison of the acid sources (H+) in isomerization of 1c to 2c. Conditions: allylbenzene (1c, 0.13 mmol, 1.0 equiv), Ni[P(OEt)3]4 (0.0036 mmol, 3.0 mol %), H + (0.0062 mmol, 5.0 mol %), and Et2O (2.0 mL). (b) Hot-filtration experiment. Conditions: 1a (0.12 mmol, 1.0 equiv), [Ni]-SZO (0.0036 mmol, 3.0 mol %), and Et2O (2.0 mL). Typical reaction conditions without filtration (green diamonds); filtered reaction (yellow triangles). Yield and selectivity determined by GC analysis using cyclooctane as an internal standard for all experiments. 74 Yield (%) Yield (%) After validating the heterogeneity of the catalyst, we investigated catalyst stability. Tolman found that the active catalyst generated from Ni[P(OEt)3]4 and H2SO4 is highly unstable, converting just 22% of 1-butene after aging the catalyst for 85 minutes, whereas 95% of 1-butene was converted when using freshly prepared catalyst.22,195 He showed that this catalyst deactivation is due to the reaction between an acid (either excess H2SO4 or the counterion HSO – 4 , which forms after protonation of Ni0) and the proposed active catalyst [Ni–H]+, generating H2 and an inactive NiII complex.194 We hypothesized that the low surface densities of acidic sites on SZO300 and the coulombic attraction of the [Ni–H]+ site to the surface anions are effectively immobilizing and localizing the active site, thereby preventing the [Ni–H]+ species from reacting with other acid sites and undergoing this detrimental deactivation pathway. To test this hypothesis and compare the stabilities of both the Ni/SZO300 and Ni/H2SO4 catalysts, both catalysts were generated and aged in Et2O for 24 hours and then their isomerization activity was compared to the activity of freshly prepared catalyst. Figure 6.3.a. shows the reaction progress over time for both catalysts and both freshly generated and aged catalysts using allylbenzene (1c) as the substrate. The freshly prepared homogeneous catalyst is highly active, reaching quantitative yield before the first aliquot was removed from the reaction for analysis (5 minutes; filled blue squares); aging this catalyst for 24 hours completely deactivates it, and no formation of 2c is measured after 2 hours (hollow blue squares). The freshly prepared heterogeneous catalyst is slower than fresh Ni/H2SO4 (as discussed above for 1a), reaching 92% yield after 2 hours (filled green diamonds); in contrast to Ni/H2SO4, aging Ni/SZO300 for 24 hours had essentially no impact on the catalyst activity (hollow green diamonds). This stability is also visually observable: both freshly prepared catalysts are bright orange (see Figure 6.1.d. for a picture of Ni/SZO300), but the homogeneous catalyst gradually becomes colorless over the first hour, and the heterogeneous catalyst retains its orange color throughout the 24-hour aging period. These data support our hypothesis that catalyst deactivation is prevented by isolating the active site. However, upon exposing [Ni]-SZO to ambient atmosphere for 1 h, the resulting catalyst was inactive for isomerization. 75 100 100 40 80 80 30 60 60 20 40 40 10 20 20 0 0 0 0 30 60 90 120 150 180 1 2 3 4 5 6 7 8 9 10 11 Time (min) Iteration ffrresh H2SO44 ffrresh SZO30000 aged H2SO44 aged SZO30000 Yield Yield (%) Selectivity (E/Z) selectivity Figure 6.3. (a) Catalyst aging study of Ni/H2SO4 (blue squares) and Ni/SZO300 (green diamonds). Conditions: 1c (0.12 mmol, 1.0 equiv), Ni[P(OEt)3]4 (0.0036 mmol, 3.0 mol %), H2SO4 or SZO300 (0.0060 mmol H+, 5.0 mol %), and Et2O (2.0 mL). (b) Catalyst recyclability study for the isomerization of 1c. Conditions: (1c, 0.060 mmol), Ni[P(OEt)3]4 (0.0018 mmol, 3.0 mol %), SZO300 (0.0030 mmol H +, 5.0 mol %), and Et2O (1.0 mL). Yield and selectivity determined by GC analysis using cyclooctane as an internal standard. The remarkable stability of the heterogeneous catalyst demonstrated in the catalyst aging study inspired us to investigate the recyclability of the catalyst. After generating the catalyst in Et2O, allylbenzene (1c) was added to the reaction at 23 °C. The reaction was allowed to stir for at least 1 h between each cycle to ensure reaction completion. After the reaction, the solution was decanted from the solid and analyzed by GC; then fresh solution of 1c was introduced to the catalyst. This process was repeated for a total of 10 cycles, giving good-to-excellent yields of 2c (Figure 6.3.b., left axis) and excellent E/Z selectivity (Figure 6.3.b., right axis) with little to no catalyst decomposition observed between each cycle (Figure 6.3.b.). Substrate Scope Having good evidence demonstrating the heterogeneity and high activity of Ni/SZO300 and using our optimized reaction conditions, we tested a library of alkenes to demonstrate the broadness of the substrate scope (Figure 6.4.). All reactions were performed using 3 mol % Ni[P(OEt)3] + 4, 5 mol % H sites in SZO300, Et2O as the solvent, and 30 °C reaction temperature, 76 Yield (%) Yield (%) Selectivity (E/Z) unless stated otherwise. We initially evaluated a variety of functional groups using the additive screening protocol (Table E.3.)213 and used those results as a guide in substrate choice. A wide range of electronically (1a-1g) varied akenes were well-tolerated, resulting in good-to-excellent yield (77-94%) and selectivity (E/Z ≥ 25:1). Adding steric bulk, as seen in substrate 1h, does not diminish the yield (97%), but the selectivity does decrease to 13:1 (E/Z). The formation of trisubstituted alkenes in high E/Z selectivity is a significant challenge in base metal-catalyzed alkene isomerization, with notable advancements using Co and Fe homogeneous catalysts recently disclosed.214–221 Isomerization of 1i, a 1,1-disubstituted alkene, to 2i, a trisubstituted alkene, gave 97% yield and modest selectivity (E/Z = 7.7:1). We hypothesized that having a slight molar excess of acidic sites relative to Ni (5 mol % and 3 mol %, respectively) under our optimized conditions might lead to intolerance of acid- sensitive functional groups. However, they are compatible, suggesting that the remaining acidic sites are inaccessible. Substrates with a methoxy methyl ether (2j) and trimethylsilyl ether (2k) were well-tolerated, giving 68% and 93% yield and 19:1 and 18:1 E/Z ratios, respectively. Substrates with functional groups that would typically deactivate late transition metal catalysts like phenol (1l; 98% yield; E/Z = >99:1), nitrile (1m; 98% yield; E/Z = 25:1), and carboxylic acid (1n; 74% yield; E/Z = >99:1) are tolerated very well, giving excellent yield and E/Z selectivity. Heterocyclic substrates are also tolerated: the indole derivative 1o yields 70% of 2o and thiophenes 1p and 1q yield 88% of 2p and 98% of 2q, respectively. However, the presence of a sulfone in 1r was not as well-tolerated, with only 37% of 1r converting to 2r. The reaction of allylthiophene 1p did not complete at 30 °C (~60% conversion was measured) but increasing the catalyst loading to 4:7 mol % Ni[P(OEt)3]4/SZO300, the reaction temperature to 50 °C, and the reaction time to 24 h gave full conversion, and 2p was isolated in 88% yield. The E/Z selectivity of products 2o and 2p is good, although lower than allylbenzene derivatives (9.5:1 and 7.4:1, respectively). The selectivity of the reaction forming product 2q reverses, favoring the Z-isomer (E/Z = 1:1.7). The switch in selectivity to favor formation of the Z isomer is also seen in phenyl allyl ether 2s (73% yield; E/Z = 1:2.8). The E- and Z-isomers of enol ethers are known to have similar thermodynamic stabilities, which informs us that the selectivity of the Ni/SZO300 catalyst is likely dictated by thermodynamics.222–224 This conclusion is supported by the data in Tables S5 and S6; at early reaction times, low E/Z ratios are measured, and the selectivity increases over time, even after conversion of the substrate completes (i.e., more of the Z-isomer is formed at the 77 beginning of the reaction, and then the Z-isomer is converted to the E-isomer as the reaction proceeds). Other challenging functional groups with heteroatoms are excellently tolerated. In addition to the amino functional group in 1o, the tosyl-protected allyl amine 1t and the amide 1u both proceed to high yield (97% and 91%, respectively) and E/Z selectivity (24:1 and >99:1, respectively). The allyl boronic ester 1v isomerized to the vinyl boronic ester 2v in 61% yield and 8.8:1 E/Z selectivity. Protected phenol derivatives 1w and 1x gave excellent yields and E/Z selectivity (97% and >99% yield; E/Z = 16:1 and 29:1, respectively). The presence of (pseudo)halides and halides in 1x and 1y, respectively, were well tolerated to yield >99% and 92%, respectively, and high selectivity (E/Z = 29:1 and >99:1, respectively). 1q, 1x, and 1y exemplify the compatibility of halides and (pseudo)halides with these catalytic conditions, holding potential for future derivatization. Likewise, the aldehyde in 1g was compatible with these reaction conditions, affording the alkene isomerization product 2g in 94% yield and >99:1 E/Z selectivity. 1-decene 1z is readily isomerized to 2-decene 2z in 88% yield with good selectivity (E/Z = 8.9:1) and a 6.7:1 ratio of the 2-decene to the 3-, 4-, and 5-decene isomers, demonstrating good positional selectivity. To rationalize the favorability of 2-decene formation over other internal isomers, the relative rates of isomerization of 1aa to 2aa and 2aa to 2ab were monitored by GC. Taking the linear portion of the first 10 min of each reaction, the isomerization of 1aa to 2aa is 55x faster than that of the isomerization of 2aa to 2ab (Figure E.4., see Appendix E for details). This is likely due to accessible binding mode of the terminal alkene (1aa) than the internal alkene (2aa) for isomerization to proceed.225 These data inspired us to evaluate the potential of controlling the positional selectivity of Ni/SZO300. Using a lower reaction temperature of 0 °C, migration of the alkene in homoallylbenzene 1aa was controlled to one bond, and 2aa was formed in 88% yield, 5.0:1 E/Z selectivity, and 14:1 positional selectivity (2aa/2ab). Using an elevated temperature (70 °C), alkene migration proceeded to the most thermodynamically favorable site, forming β- ethylstyrene 2ab in 87% yield, >99:1 E/Z selectivity, and 1:16 positional selectivity (2aa/2ab). To show the practicality of this Ni/SZO300 catalyst, we performed the isomerization of 1a on a 1.26 g scale (8.53 mmol) under optimized reaction conditions. 1a proceeded to complete conversion to 2a after 2 h. The product was purified by a simple filtration to remove the solid 78 Figure 6.4. (a) Substrate scope for isomerization using Ni/SZO300. Isolated yields and selectivity (E/Z) of the isolated products are reported. The selectivity was determined by relative integrations in the 1H NMR. Conditions: 1 (1.0 mmol, 1.0 equiv), Ni[P(OEt)3]4 (0.030 mmol, 3.0 mol %), SZO300 (0.050 mmol H +, 5.0 mol %), Et2O (17 mL), 30 °C, 1-24 h. (b) Substrate scope with Ni/H2SO4. Conversion is reported as % conversion to product. Conversion and selectivity were determined by GC or GC-MS. Conditions: 1 (0.060 mmol), Ni[P(OEt)3]4 (0.0018 mmol, 3.0 mol %), H2SO4 (0.0030 mmol H +, 5 mol %), Et2O (1.0 mL). Ts, tosyl; TMS, trimethylsilane, Ac, acyl. a50 °C. b0.87 mmol 1i, 3.4 mol % Ni[P(OEt)3]4, 5.6 mol % SZO c 300. 0.68 mmol 1p, 4.4 mol % Ni[P(OEt)3] d 4, 7.4 mol % SZO300. Isolated as a mixture of 1r and 2r. e0 °C. f70 °C. catalyst and concentration to give product 2a. This straightforward process gave an excellent isolated yield of 98% (1.24 g, 8.37 mmol) while retaining high E/Z selectivity of 33:1 (E/Z). These results paired with the diverse functional group tolerance showcase the potential usefulness of this heterogeneous [Ni–H]+ isomerization catalyst. 79 As an effort to simply the system, we wondered if the pre-heat treated SZO300 precursor, Zr(OH)4•H2SO4, was a viable acid source for alkene isomerization. Under standard reaction conditions, Zr(OH)4•H2SO4 was used in place of SZO300 for the isomerization of 1c to 2c. Analysis by GC shows that at 80 minutes, the reaction reaches 88% yield with good E-selectivity of 20:1, which is comparable to that of using SZO300 (81% yield and E/Z = 26:1). At 120 minutes, the yield remains the same (90%) while E-selectivity continues to rise (E/Z = 27:1) similarly to that of the Ni/SZO system (90% yield, E/Z = 30:1). As a test to confirm that the Ni/Zr(OH)4•H2SO4 system behaved the same as the Ni/SZO, we tested the isomerization of 1t, an alkene that was incompatible with Ni/H2SO4, on a 1 mmol scale under standard conditions. After 24 h, 1H NMR analysis of the crude reaction indicates 9% of unreacted 1t, 65% of 2t with low E-selectivity of 6.2:1 (E/Z), as well as deallylated 1t to form the 2° amine, S1 (see Appendix E for details). Both Ni and Pd have been previously reported to undergo deallylation of amines.226,227 Although the isomerization of 1t to 2t was observed by Ni/Zr(OH)4•H2SO4, the low E/Z selectivity and competing side reaction deems this catalytic system less effective than the Ni/SZO system. This highlights the crucial role that SZO has in alkene isomerization efficiency and activity. Comparison of Ni/SZO300 to Homogeneous Catalysts A subset of the substrates included in Figure 6.4.a. were also evaluated for isomerization using Ni/H2SO4, the homogeneous analog of Ni/SZO300, using standard conditions (Figure 6.4.b.). With a few exceptions, we found that the heterogeneous catalyst is generally more compatible with more functional groups and is more selective. Substrates 1t and 1v are incompatible with Ni/H2SO4 (≤1% conversion), and substrates 1m and 1q give very low conversions to the isomerized product (3% and 13%, respectively), but all of these substrates give excellent yields with Ni/SZO300 (97%, 61%, 98%, and 98%, respectively). Notably, we have not found a substrate that is compatible with Ni/H2SO4 and incompatible with the heterogeneous Ni/SZO300 catalyst, highlighting the unique advantages offered by this heterogeneous catalyst. Ni/H2SO4 outcompeted Ni/SZO300 with only one identified substrate, 1l: >99% conversion and >99:1 E/Z selectivity in <30 min with Ni/H2SO4, 98% yield and >99:1 E/Z selectivity in 4 h with Ni/SZO300. Ni/H2SO4 took 24 hours to catalyze 1o to 2o in 65% conversion with an E/Z ratio of >99:1, but this substrate reached complete conversion and higher E/Z ratio of 9.5:1 (E/Z) in just 8 hours with Ni/SZO300. Conversion of 1f, 1j, and 1k using Ni/H2SO4 was high (>99% for all) after less than 30 minutes, while the Ni/SZO300 catalyst 80 required 5 hours, 8 hours, and 5 hours, respectively, to reach similar conversion. However, for all alkenes 1j, and 1k the E/Z selectivity with Ni/SZO300 (19:1, and 18:1, respectively) was significantly better than with Ni/H2SO4 (5.4:1 and 4.4:1, respectively). Further demonstrating the advantage of using Ni/SZO300 over its homogeneous analog, approximately 1% of the deprotected phenol (2l) was observed after just 30 minutes of reaction time with substrate 1k. A longer reaction time of 24 h to form 2j and 2k with Ni/H2SO4 revealed further deprotection of 2j and 2k to form 2% and 20% 2l, respectively, while no evidence of deprotection was present with Ni/SZO300. We wondered if positional selectivity could also be achieved using the Ni/H2SO4 system. At 0 °C, 90% 1aa was converted to 2aa with improved positional (2aa/2ab = 66:1) but with diminished E- selectivity (E/Z = 2.9:1) as the Ni/SZO300 system (2aa/2ab = 14:1, E/Z = 5.0:1). On the contrary, the Ni/H2SO4 catalyst was rather unstable at 70 °C revealed by the low conversion of 1aa to 2ab (5%) and poor positional selectivity (2aa/2ab = 1:1.5). These results further show the advantages of having enhanced catalyst stability, seen in the Ni/SZO300 system, compared to the much less stable homogeneous analog. To further demonstrate the exceptional performance of Ni/SZO300, we sought to compare its activity and selectivity to those from other state-of-the-art homogeneous Ni and Pd catalysts (Figure 6.5.). Schoenebeck,228 Engle,229 our lab,230 and others4,47–52 have recently developed Ni- catalyzed isomerization catalysts that are E-selective. Additionally, Skrydstrup reported a Pd- catalyzed isomerization system that is highly compatible with a diverse set of alkene-containing substrates.237 Despite the rich display of reactivity exhibited by these homogeneous catalysts, minimal work has been done to unveil relative isomerization rates. We initiated our studies by monitoring the formation of 2a from 1a over time for the following systems: Ni[P(OEt)3]4/SZO300 (A; this work); (IPr)2Ni2Cl2 (B; Schoenebeck; 228 IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene), Ni(cod)2/PCy3•HBF4, (C; Engle; 229 cod = cyclooctadiene; Cy = cyclohexyl), (IPr)Ni(hex)/HSiPh3, (D; Cook; 230 hex = 1,5-hexadiene), and Pd(dba)2/P(t-Bu)3/i-PrC(O)Cl (E; Skrydstrup; 237 dba = dibenzoylacetone). Each isomerization reaction was performed under its respective optimized conditions and the product formation over time was measured by GC (Figure 6.5.). Monitoring the reactions over time, we see that all but system D (Figure 6.5., yellow triangles) reach completion by 180 min. Due to the induction periods observed for systems C and 81 100 80 60 40 20 0 0 30 60 90 120 150 180 Time (min) Figure 6.5. Kinetic analysis of Ni and Pd isomerization catalysts. 1a (0.12 mmol unless otherwise stated). aNi[P(OEt)3]4 (0.0036 mmol, 3.0 mol %), SZO + 300 (0.0060 mmol H , 5.0 mol %), Et2O (2.0 mL), 30 °C. b(IPr)2Ni2Cl2 (0.0060 mmol, 5.0 mol %), ClC6H5 (0.3 mL), 30 °C. c(IPr)Ni(hex) (0.0060 mmol, 5.0 mol %), HSiPh3 (0.0061 mmol, 5.0 mol %), hexanes (0.38 mL), 80 °C. d1a (0.25 mmol), Ni(cod)2 (0.025 mmol, 10 mol %), PCy3•HBF4 (0.027 mmol, 11 mol %), NBu4Br (0.12 mmol), H2O (0.12 mmol), DMF (5.0 mL), 30 °C. ePd(dba)2 (0.00061 mmol, 0.50 mol %), P(t-Bu)3 (0.00061 mmol, 0.50 mol %), i-PrC(O)Cl (0.00061 mmol, 0.50 mol %), toluene (2.9 mL), 80 °C. IPr, (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene); cod, 1,5-cyclooctadiene; hex, 1,5-hexadiene; dba, dibenzylideneacetone. D, linear rates were not calculated to compare relative isomerization rates between each system. Visual analysis of the reaction progress over time reveal that systems B, C, and D all exhibit slower reaction kinetics than A and E. It is notable that system A (Ni/SZO300) is performed at 30 °C using 3 mol % Ni, while system E requires an elevated reaction temperature of 80 °C, but performs well using just 0.5 mol % Pd. The corresponding selectivity profile for systems C, D, and E equilibrates to ~15:1 (E/Z) at 3 h, whereas systems A and B gradually increase over time to ~30:1 E/Z by 3 h (Figure S30). These catalyst systems were also all compared at equal catalyst loadings (3 mol % Ni or Pd and 3 mol % additive/ligand) and reaction temperature (30 °C), but with each respective system’s optimal reaction solvent and concentration (Figures E.41.-E.42.). Ni/SZO300 reaches completion in ~90 min (91% yield), systems B, D, and E reach ~20% conversion after 150 min, and system C does not produce any product. Both Ni/SZO300 and B reach the highest selectivity 82 Yield (%) after 2 h compared to the other catalysts. These data further demonstrate the excellent performance of Ni/SZO300, even in comparison to the state-of-the-art Ni and Pd catalysts. Mechanistic Studies Having successfully developed a heterogeneous isomerization catalyst with a large substrate scope, we embarked on preliminary mechanistic investigations. We hypothesized that the heterogeneous catalyst has similar reaction and catalyst activation mechanisms as the Ni/H2SO4 catalyst. Alkene isomerization most often occurs via 1) a radical mechanism, 2) Callylic– H activation to form a metal-allyl intermediate, and 3) M–H (M = metal) insertion/elimination pathways.172–176 Tolman demonstrated that the homogeneous Ni/H2SO4 catalyst proceeds though a M–H insertion/elimination pathway,195 so we hypothesized that Ni/SZO300 would operate under the same mechanism. To probe whether a radical pathway is occurring, we tested the reaction of Ni[P(OEt)3]4 with 1ac (Scheme 6.1.a.). If isomerization proceeds through a radical pathway, a few rearrangement products are possible.214,238,239 However, none were observed at 30 °C, 50 °C, and 70 °C, implying that a radical pathway is not proceeding. This result also suggests that there is no or very little Ni(0) present, since Ni(0) complexes are known to oxidatively add to cyclopropane rings and rearrange the carbon skeleton.230,240 As an additional radical probe, the 1,6-diene 1ad, which is expected to cyclize to form a methylenecyclopentane under radical conditions, shows only alkene isomerization with Ni/SZO300 (Scheme 6.1.b.). After reacting 1ad for 5 h at 30 °C, 97% of 1ad was converted to the 1,5-diene (2ad), and no trace of cyclized product was identified by GC or 1H NMR, further confirming that this reaction is likely not going through a radical pathway.230,240 We next wanted to distinguish between an allyl (intramolecular) or Ni–H insertion- elimination (intermolecular) mechanism. A crossover experiment was performed with 0.5 equiv 1a and 0.5 equiv 1c-dn (Scheme 6.1.c.). If an allyl pathway is occurring, no protium/deuterium scrambling between the two substrates is expected.173 Deuterium incorporation into 2a and protium incorporation into 2c-dn is predicted if the mechanism proceeds via a Ni–H insertion/elimination mechanism, since the Ni–H/D formed during the reaction could exchange one alkene ligand for another. Analysis of the products by 1H and 2H NMR revealed significant protium/deuterium scrambling in both 2a and 2c-dn, supporting the viability of an intermolecular, Ni–H insertion- elimination pathway (Figures E.28.-E.30.). 83 Potential of Ni/SZO300 in Additional Catalytic Reactions As metal–hydrides are often invoked in catalysis, our final goal is to demonstrate the broad utility of this heterogeneous catalyst by evaluating its activity in other catalytic reactions. Metal- catalyzed alkene hydrofunctionalization reactions offer access to value-added chemicals by installing structural diversity.241–245 Specifically, hydroalkenylation is utilized in the Shell higher olefin process to produce 1x106 tons of olefins annually.246 Additionally, hydroboration247,248 products are excellent Suzuki-Miyaura cross-coupling partners to construct C–C bonds in organic synthesis.249–251 Hydrosilylation reactions produce valuable organosilicon compounds used in reactions like Hiyama couplings for C–C bond formation,252,252 Tamao-Fleming oxidations to form alcohols,253–256 and polymerizations to form silicone materials257–259 Ni/SZO300 is a viable catalyst for hydroalkenylation, hydroboration, and hydrosilylation of alkenes (Figure 6.6.). Notably, the results of these Ni/SZO300-catalyzed reactions are unoptimized. Ni/SZO300 is an excellent styrene hydroalkenylation catalyst, affording 94% yield (determined 1H NMR spectroscopy using an internal standard) of product 3a, with no evidence of formation of the other hydrovinylation isomers. Hydroboration260,261 of the vinyl amide 2u using B2pin2, LiOt-Bu, and MeOH resulted in 55% yield of product 3b (determined by GCMS using an internal standard); like hydrovinylation, this reaction is highly selective, and product 3b is the only isomer observed by both GC-MS and 1H NMR spectroscopy. Lastly, styrene is hydrosilylated262 by Ph2SiH2 using catalyst Ni/SZO300, giving 21% yield of 3c in 7:1 selectivity (branched/linear), as determined by GC-FID using an internal standard. These results demonstrate the potential for broad utility that this novel heterogeneous catalyst, Ni/SZO300, holds. 84 Scheme 6.1. Mechanistic experiments. (a) Reactivity with vinylcyclopropane (1ac). (b) Reactivity with a 1,6-diene (1ad). (c) Crossover experiment between 1a and 1c-dn. aConditions: 1ac (0.060 mmol), Ni[P(OEt)3]4 (0.0018 mmol, 3.0 mol %), SZO300 (0.0030 mmol H+, 5.0 mol %), Et2O (1.0 mL). bConditions: 1ad (1.0 mmol), Ni[P(OEt)3]4 (0.030 mmol, 3.0 mol %), SZO300 (0.050 mmol H +, 5.0 mol %), Et2O (17 mL). c1a (0.28 mmol, 0.50 equiv), 1c-dn (0.28 mmol, 0.50 equiv), Ni[P(OEt)3]4 (0.017 mmol, 3.0 mol %), SZO300 (0.028 mmol H +, 5.0 mol %), Et2O (9.6 mL). Figure 6.6. [Ni–H]+-catalyzed reactions under unoptimized conditions. (a) Hydroalkenylation of styrene to afford 3a. (b) hydroboration of 2u and B2Pin2 to afford 3b. (c) Hydrosilylation of styrene and H2SiPh2 to afford 3c. 85 6.3 Conclusion The combination of Ni[P(OEt)3]4 and SZO300 generates a potent alkene isomerization catalyst, with marked improvement over previous work that used sulfated polymers to heterogenize the Ni[P(OEt)3] + 4/H isomerization system. Ni/SZO300 is heterogeneous in nature, as demonstrated by a hot-filtration test, and is highly recyclable and robust, as demonstrated with catalyst aging studies. Remarkably, the substrate scope is very broad and includes various heteroatoms, acid-labile groups, halides, carboxylic acids, and amides. The catalyst can also be kinetically controlled to achieve specific positional isomers when using a long chain alkene. Preliminary mechanistic results suggest against radical and allyl pathways but do allude to a M–H insertion/elimination mechanism for alkene isomerization. Ni/SZO300 also outcompetes state-of- the-art homogeneous Ni and Pd catalysts in head-to-head comparisons, in terms of both reaction rates and selectivity. The rational approach to designing this active site led to a heterogeneous catalyst with significantly increased catalyst versatility over its homogeneous counterpart. 86 APPENDIX A SUPPLEMENTARY CONTENT FOR CHAPTER II Experimental details A.1.1. Materials and Methods All syntheses and manipulations were carried out under nitrogen using standard Schlenk (vacuum 10-2 mbar) techniques or in a nitrogen-filled glovebox unless otherwise indicated. All reagents and solvents were used after drying and stored under nitrogen, unless otherwise indicated. Tetrahydrofuran (THF; Fisher Chemical; HPLC grade, unstabilized), hexanes (Fisher Chemical; HPLC grade), diethyl ether (B&J Brand; HPLC grade, unstabilized) and acetonitrile (Fisher Chemical; HPLC grade) were dispensed under nitrogen from an LC Technology SP-1 solvent system. Benzene (ACS grade) and pentane (HPLC grade) were refluxed overnight with CaH2 and distilled under nitrogen before use. The dried solvents were thereafter stored on activated 4Å molecular sieves under nitrogen. CD3CN, C6D6 and CDCl3 were purchased from Cambridge Isotope Laboratories, degassed by freeze-pump-thaw, and thereafter stored on activated 4Å molecular sieves under nitrogen. All stock solutions were prepared by mass and were dispensed into the reaction vessel by difference from syringe, as detailed in the procedure for each experiment. The following reagents were used from commercial sources without further purification: N,N’-dimethylthiourea (TCI), acetoin (TCI), potassium (Acros), 2,6-diisopropylaniline (TCI), 2,4,6-trimethylaniline (TCI), glyoxal (40 wt%, Sigma Aldrich), paraformaldehyde powdered (Oakwood Chemical), glacial acetic acid (Fisher Chemical, ACS grade), formic acid (Fisher Scientific), HCl (4M in dioxanes; Oakwood), trimethylsilylchloride (TCI), tetrafluoroboric acid (50 wt%; Beantown Chemical), potassium tert-butoxide (Strem, Oakwood Chemical), sodium hydride (60% dispersion in mineral oil; Aldrich), bis(1,5-cyclooctadiene)nickel(0) (Ni(cod)2; Strem), allyl ether (TCI), 1,3-divinyltetramethyldisiloxane (dvtms, TCI), 1,5-hexadiene (TCI), allyl bromide (Aldrich Chemical), methyltriphenylphosphonium bromide (TCI), 4- (dimethylamino)benzaldehyde (Aldrich), 4-(trifluoromethyl)benzaldehyde (Alfa Aesar), 2- thiophenecarboxaldehyde (Aldrich), diisopropylamine (DIPA; Acros), 4-dimethylaminopyridine (DMAP; Aldrich), triethylamine (TEA; EM Science), 4-hydroxybenzaldehyde (Sigma), p- 87 toluenesulfonyl chloride (TCI), chloromethylmethylether (Sigma Aldrich), potassium carbonate (Fisher Chemical, ACS grade), lithium aluminum hydride (Aldrich), magnesium (Acros), iodine (Mallinckrodt), 4-bromoanisole (TCI), 4-bromotoluene (Aldrich), 1-bromo-3-fluorobenzene (Aldrich), 4-bromobenzotrifluoride (Matrix Scientific), 3-bromotoluene (Fluka), 2-bromotoluene (Aldrich), 2-bromomesitylene (Acros), 1-bromo-4-chlorobenzene (TCI), styrene (2a; TCI), 4- methoxystyrene (2c; Alfa Aesar), 4-tert-butylstyrene (2d; TCI), 4-methylstyrene (2e; TCI), 4- fluorostyrene (2f; Matrix), 2-methylstyrene (2h; TCI), 2-vinylnaphthalene (2i; Alfa Aesar), trans- β-methylstyrene (2j; TCI), 3,3-dimethyl-1-butene (2m; Acros), vinylcyclohexane (2n; TCI), 1- decene (2o; TCI), benzaldehyde (2p; Sigma Aldrich), acetophenone (2q; Sigma Aldrich), acetone (2r; Fisher Chemical, ACS grade), phenylacetylene (Aldrich), (+/-)-limonene (TCI), cyclooctene (Acros), diphenylsilane (3a; Oakwood), diethylsilane (3j; Alfa Aesar), 1-naphthylphenylsilane (3i; Sigma Aldrich), methyldiphenylsilane (3n; Alfa Aesar), dimethylphenylsilane (3o; TCI), triphenylsilane (3l; Thermo Scientific), triethoxysilane (3p; Acros), 1,1,1,3,5,5,5- heptamethyltrisiloxane (3q; TCI), trichlorosilane (3r; Alfa Aesar), dichloromethylsilane (3s; Alfa Aesar), dichlorodiphenylsilane (TCI), trichlorophenylsilane (TCI), and durene (Eastman Chemical Company). 1c was synthesized via reported procedure.6,125 A.1.2. General Experimental Nuclear magnetic resonance (NMR) spectra were collected at room temperature (298 K) unless otherwise stated on a Bruker AV-III HD 600 NMR (600.13 MHz for 1H; 150.90 MHz for 13C; 564.69 MHz for 19F; 119.23 MHz for 29Si; 92.12 MHz for 2H), Bruker Avance-III HD 500 NMR (499.90 MHz for 1H; 126 MHz for 13C; 471 MHz for 19F; 99 MHz for 29Si), or Varian Inova 500 NMR (499.90 MHz for 1H; 126 MHz for 13C; 471 MHz for 19F; 99 MHz for 29Si). 1H and 13C spectra were referenced to the residual solvent peak (CDCl3: 1H δ = 7.26 ppm, 13C δ = 77.16 ppm; C6D6: 1H δ = 7.16 ppm, 13C δ = 128.06 ppm, CD CN: 13 H δ = 1.94 ppm, 13C δ = 1.32 ppm (NCCD3)). Chemical shifts for 1H, 13C, and 29Si NMR spectra are reported in parts per million (ppm, δ) relative to tetramethylsilane at 0.00 ppm. Peaks are characterized as follows: s (singlet), d (doublet), t (triplet), q (quartet), pent (pentet), hept (heptet), m (multiplet), qd (quartet of doublets), br (broad), app (apparent), and/or ms (multiple signals). Coupling constants, J, are reported in Hz. 1JH–Si 88 coupling constants were determined, when possible, using the 29Si satellites in the 1H NMR spectrum. Infrared (IR) spectroscopy for air-stable organic compounds was performed on an Agilent Nicolet 6700 FT-IR using the ATR sampling technique. IR spectra for air-sensitive nickel complexes were recorded as self-supported pellets diluted with KBr using a Bruker Alpha II FT- IR spectrometer that is housed in a nitrogen-filled glovebox. All bands are reported in wavenumbers (cm-1) and are described as broad (br), strong (s), medium (m), and weak (w). For catalytic reactions, yields were determined using Gas Chromatography-Mass Spectrometry (GC-MS) or Gas Chromatography-Flame Ionization Detector (GC) against an internal standard. GC-MS was carried out on a Shimadzu GC-2010 Plus/GCMS-QP2010 SE using a Restek Rtx®- 5 (Crossbond 5% diphenyl – 95% dimethyl polysiloxane; 15 m, 0.25 mm ID, 0.25 μm df) column. GC was carried out on a Thermo Fisher Trace 1300 Gas Chromatograph using a Restek Rtx®-5 (Crossbond 5% diphenyl – 95% dimethyl polysiloxane; 15 m, 0.25 mm ID, 0.25 μm df) column. High-resolution mass spectrometry (HRMS) was carried out on a Waters XEVO G2-XS TOF mass spectrometer. A.1.3. Synthesis of Reagents a. Synthesis of Ligands and Nickel Complexes 1,3,4,5-Tetramethylimidazole-2(3H)-thione (L1) was synthesized in accordance with a literature procedure:263 To a 250-mL Schlenk flask equipped with a stir bar was added N,N’- dimethylthiourea (4.2 g, 40 mmol, 1.0 equiv), acetoin (3.5 g, 40 mmol, 1.0 equiv) and 1-hexanol (100 mL). The reaction was refluxed for 12 h while stirring. The reaction was cooled to room temperature and the solvent was distilled off under reduced pressure. The flask was opened to atmosphere, washed with water (50 mL), followed by Et2O (50 mL) and then filtered over a fine frit to yield L1 as an off-white powder. (3.9 g, 25 mmol, 62% yield). NMR spectra match values previously reported.263 89 1,3,4,5-Tetramethylimidazol-2-ylidene (ITMe) was synthesized in accordance with literature a procedure:263 To a 100-mL Schlenk Flask equipped with a stir bar was added L1 (1.2 g, 7.7 mmol, 1.0 equiv) and THF (45 mL) and the reaction was cooled to 0 °C in an ice/water bath while stirring. To this, potassium chunks (0.73 g, 19 mmol, 2.5 equiv) were added. The reaction was warmed to room temperature and then refluxed for 4 h. The reaction was cooled to room temperature, the solid was separated by filtration using a medium-porosity frit under N2, and the filtrate was concentrated to yield ITMe as a white powder. (0.81 g, 6.5 mmol, 85% yield). NMR spectra match values previously reported.263 N,N’-Bis(2,4,6-trimethylphenyl)ethane-1,2-diimine (L2) was synthesized in accordance with literature procedure:264 Without exclusion of air and moisture, in a 25-mL round-bottom flask equipped with a stir bar was added 2,4,6-trimethylaniline (3.0 g, 22 mmol, 2.0 equiv) in methanol (10 mL). To this stirring solution, glyoxal (40 wt%, 1.3 mL, 11 mmol, 1.0 equiv) and formic acid (2 drops) were added. The reaction was capped and stirred for 15 h at room temperature. The product was collected via vacuum filtration, washed with methanol (3 x 10 mL) and dried under vacuum to obtain L2 as a bright yellow powder (2.5 g, 8.5 mmol, 77% yield). NMR spectra match values previously reported.264 90 1,3-Bis(2,4,6-trimethylphenyl)imidazolium chloride (IMes∙HCl) was synthesized in accordance with literature procedure:264 Without exclusion of air or moisture, in a 50-mL round bottom flask equipped with a stir bar, L2 (2.5 g, 8.5 mmol, 1.0 equiv) was dissolved in ethyl acetate (17 mL) and heated to 70 °C while stirring. In a separate 10-mL round bottom flask equipped with a stir bar was added paraformaldehyde (0.28 g, 9.3 mmol, 1.1 equiv) and HCl (4 M in dioxanes, 3.2 mL, 13 mmol, 1.5 equiv) and was stirred at 70 °C until all solids dissolved. The paraformaldehyde solution was added dropwise to the stirring solution of L2. The reaction was stirred at 70 °C for an hour, removed from the heat, allowed to cool to room temperature, and stirred overnight. The product was collected via vacuum filtration, washed with ethyl acetate (3 x 10 mL) and dried under reduced pressure to yield IMes∙HCl as a fluffy yellow powder (2.9 g, 8.5 mmol, 99% yield). NMR spectra match values previously reported.264 1,3-Bis(2,4,6-trimethylphenyl)imidazolium tetrafluoroborate (IMes∙HBF4) was synthesized in accordance with literature procedure:264 Without exclusion of air or moisture, in a 50-mL round bottom flask equipped with a stir bar was added IMes∙HCl (2.3 g, 6.7 mmol, 1.0 equiv) and a minimal amount of water (10 mL). The mixture was stirred until IMes∙HCl was dissolved. HBF4 (50 wt%, 0.91 mL, 7.3 mmol, 1.1 equiv) was added to the stirring solution and a white precipitate immediately formed. This mixture was stirred for 20 min at room temperature. The product was extracted with dichloromethane (3 x 100 mL) and the organic layers were combined, and dried with MgSO4, filtered, and concentrated under reduced pressure. The product was purified by solvating the crude product in minimal amounts of dichloromethane (3.0 mL) and then precipitated by the addition of diethyl ether (50 mL). The product was collected via vacuum filtration, washed 91 with diethyl ether (50 mL), and dried under reduced pressure to yield IMes∙HBF4 as a white powder (2.0 g, 5.1 mmol, 76% yield). NMR spectra match values previously reported.264 1,3-Bis(2,4,6-trimethylphenyl)-1,3-dihydro-2H-imidazol-2-ylidene (IMes) was synthesized in accordance with literature procedure:264 In a 100-mL round bottom flask equipped with a stir bar was added IMes∙HBF4 (2.0 g, 5.1 mmol, 1.0 equiv) in THF (20 mL). The mixture was stirred upon the slow addition of NaH (60% dispersion in mineral oil, 0.40 g, 10 mmol, 2.0 equiv) and t-BuOK (a spatula tip-ful). The reaction was vented for the first 15 min to release the initial formation of H2 (g), capped, and stirred overnight at room temperature. After stirring for 16 h, the reaction mixture was filtered through a pad of Celite, and the filtrate was concentrated. The crude product was solvated in minimal amounts of THF (5.0 mL), hexanes was added (50 mL), and the vessel was capped and placed in the freezer (-30 °C). The product was collected via vacuum filtration, washed with cold hexanes, and dried under reduced pressure to obtain IMes as off-white crystals (0.93 g, 3.1 mmol, 60% yield). NMR spectra match values previously reported.264 (1E,2E)-1,2-Bis(2,6-Diisopropylphenylimino)ethane (L3) was synthesized in accordance with literature procedure:264 Without exclusion of air or moisture, to a 50-mL round bottom flask equipped with a stir bar was added 2,6-diisopropylaniline (3.0 g, 17 mmol, 2.0 equiv), glacial acetic acid (a few drops), and i-PrOH (10 mL) and stirred at 50 °C. To this solution, a mixture of glyoxal (40 wt%, 0.97 mL, 8.5 mmol, 1.0 equiv) and i-PrOH (5.0 mL) was added dropwise. After the addition of reagents, the reaction was lifted from the heat and slowly cooled to room temperature and stirred for 16 h. The crude mixture was placed in the freezer (- 25 °C) for 5 hours. 92 The product was collected via vacuum filtration, washed with i-PrOH (20 mL), and dried under reduced pressure to afford L3 as a yellow powder (2.4 g, 6.4 mmol, 75% yield). NMR spectra match values previously reported.264 1,3-Bis(2,6-diisopropylphenyl)imidazolium chloride (IPr∙HCl) was synthesized in accordance with literature procedure:265 Without exclusion of air or moisture, to a 50-mL round bottom flask equipped with a stir bar was added L3 (2.2 g, 5.8 mmol, 1.0 equiv), paraformaldehyde (0.17 g, 5.8 mmol, 1.0 equiv), and EtOAc (12 mL). The mixture was heated to 70 °C and stirred for 30 min. A solution of trimethylsilylchloride (0.75 mL, 5.9 mmol, 1.0 equiv) in EtOAc (5.0 mL) was added dropwise to the solution and the reaction was left to stir at 70 °C for 2 h. The reaction was taken off the heat to cool to room temperature and then placed in the freezer (-25 °C) overnight. The product was collected via vacuum filtration, washed first with EtOAc (10 mL) followed by tert- butyl methyl ether (10 mL), and dried in an oven at 100 °C for 4 h to yield IPr∙HCl as a white powder (1.7 g, 4.0 mmol, 69% yield). NMR spectra match values previously reported.264 1,3-Bis(2,6-diisopropylphenyl)-1H-imidazol-3-ium tetrafluoroborate (IPr∙HBF4) was synthesized in accordance with literature procedure:264 Without exclusion of air or moisture, to a 50-mL round bottom flask equipped with a stir bar was added IPr∙HCl (1.5 g, 3.5 mmol, 1.0 equiv) and a minimal amount of water (7.0 mL) until all solids dissolved. HBF4 (50 wt%, 0.48 mL, 3.9 mmol, 1.1 equiv) was added and immediately a white precipitate formed. This mixture was stirred for 20 min at room temperature. The product was extracted with dichloromethane (3 x 100 mL) 93 and the organic layers were combined and dried with MgSO4, filtered, and concentrated under reduced pressure. The product was purified by dissolving the crude product in minimal amounts of dichloromethane (3.0 mL) and then precipitating out with the addition of diethyl ether (50 mL). The product was collected via vacuum filtration, washed with diethyl ether (50 mL), and dried under reduced pressure to yield IPr∙HBF4 as a white powder (1.5 g, 3.2 mmol, 90% yield). NMR spectra match values previously reported.264 1,3-Bis(2,6-diisopropylphenyl)-1,3-dihydro-2H-imidazol-2-ylidene (IPr) was synthesized in accordance with literature procedure:264 To a 50-mL round bottom flask equipped with a stir bar was added IPr∙HBF4 (1.5 g, 3.2 mmol, 1.0 equiv) and THF (15 mL). To this solution, NaH (60% dispersion in mineral oil, 0.15 g, 3.8 mmol, 1.2 equiv) and t-BuOK (spatula tip-ful) were added slowly. The reaction vessel was vented for 15 min while stirring to allow the initial H2 (g) production to be released, capped, and stirred for 16 h at room temperature. The reaction was filtered through a pad of Celite, and the filtrate was concentrated under reduced pressure. The crude product was dissolved in minimal amounts of THF (4 mL) and then hexanes (50 mL) was added to crystallize the product to obtain IPr as a white powder (0.41 g, 1.0 mmol, 33% yield). NMR spectra match values previously reported.264 (dvtms)Ni(ITMe) (1a): To a 4-dram scintillation vial equipped with a magnetic stir bar was added Ni(cod)2 (0.10 g, 0.36 mmol, 1.0 equiv) in THF (5.0 mL). To the stirring solution was added dvtms (0.34 mL, 1.5 mmol, 4.1 equiv). After 1 min of stirring, ITMe (0.046 g, 0.37 mmol, 1.0 equiv) 94 solvated in THF (5.0 mL) was added and the reaction turned into a bright orange solution. The reaction was left to stir overnight and then concentrated under reduced pressure. The crude product was solvated in minimal hexanes (5.0 mL) and filtered through Celite. The solution was concentrated to a third of its volume and crystallized in the freezer at -30 °C overnight. The filtrate was decanted, and the solid was dried under reduced pressure to yield 1a as shiny, white crystals (76 mg, 0.21 mmol, 57% yield). 1H NMR (500 MHz, C6D6, 298 K): δ 2.97 (s, 3H, NCH3), 2.91 (d, J = 12.1 Hz, 2H, HC=CHcis), 2.79 (s, 3H, NCH3), 2.67 (d, J = 15.5 Hz, 2H, HC=CHtrans), 2.58 (dd, J = 15.5, 12.1 Hz, 2H H2C=CH), 1.44 (d, J = 0.9 Hz, 3H, CCH3), 1.41 (d, J = 0.9 Hz, 3H, CCH3), 0.72 (s, 6H, SiCH3), 0.18 (s, 6H, SiCH3). 13C{1H} NMR (126 MHz, C6D6, 298 K): δ 199.2 (NiC), 124.4 (N-C=C), 124.3 (N-C=C), 52.7 (SiC=CH2), 50.5 (SiC=CH2), 33.7 (NCH3), 33.4 (NCH3), 8.48 (C=C-CH3), 8.46 (C=C-CH3), 2.6 (SiCH3), -0.2 (SiCH3). 29Si NMR (99 MHz, C6D6, 298 K): δ 3.00 (s). IR (FT, KBr pellet) ν: 3002-2782 (s), 1660 (w), 1380 (s), 983 (s), 775 (s). ASAP/HRMS (m/z): [M+] calculated for C15H30N2NiOSi2 368.1250, found 368.1241. (dvtms)Ni(IMes) (1b) was synthesized via a modified route:130 To a round bottom flask equipped with a magnetic stir bar was added 1d (0.050 g, 0.10 mmol, 1.0 equiv) and toluene (0.50 mL). To this stirring solution, dvtms (0.24 µL, 0.10 mmol, 1.0 equiv) was added, resulting in the solution turning dark red. The reaction turned orange after stirring for 6 h. The solution was concentrated under reduced pressure and the crude solid was redissolved in minimal hexanes (3.0 mL) and filtered through Celite into a scintillation vial. Half of the solvent was removed under reduced pressure and the remaining solution was placed in the freezer (-30 °C) for 2 h. The product precipitated and was isolated by filtration through a glass frit, yielding 1b as pale orange crystals (0.037 g, 0.068 mmol, 68% yield). 95 1H NMR (500 MHz, C6D6, 298 K): δ 6.69 (s, 4H, Hmesityl), 6.32 (s, 2H, NCH), 2.75 (d, J = 12.7 Hz, 2H, HC=CHcis), 2.45 (d, J = 16.0 Hz, 2H, HC=CHtrans), 2.11 (s, 12H, Cmesityl-CH3), 2.09 (obscured dd, H2C=CH), 2.06 (s, 6H, Cmesityl-CH3), 0.46 (s, 6H, SiCH3), -0.33 (s, 6H, SiCH3). 13C{1H} NMR (151 MHz, C6D6, 298 K): δ 202.9 (NiC), 138.4 (Cmesityl), 137.6 (Cmesityl), 135.4 (CmesitylCH3), 129.3 (CmesitylH), 122.8 (N-C=C), 53.9 (SiC=CH2), 53.4 (SiC=CH2), 20.9 (CmesitylCH3), 18.4 (CmesitylCH3), 2.4 (SiCH3), -0.9 (SiCH3). IR (FT, KBr pellet) ν: 3153-2861 (s), 1481 (s), 1308 (s), 971 (s), 784 (s). ASAP/HRMS (m/z): [M+] calculated for C29H42N2NiOSi2 548.2189, found 548.2193. (dvtms)Ni(IPr) (1c) was synthesized via a reported procedure.125 NMR spectra match values previously reported.125 (1,5-hexadiene)Ni(IMes) (1d) was synthesized via a modified route:125 To a 20-mL scintillation vial equipped with a stir bar was added Ni(cod)2 (0.5 g, 1.8 mmol, 1.0 equiv) and THF (5.0 mL). To this stirring solution was added 1,5-hexadiene (3.2 mL, 27 mmol, 15 equiv) and the reaction was allowed to stir for 10 min to afford a red/orange solution. In a separate vial was added IMes (0.55 g, 1.8 mmol, 1.0 equiv) and THF (5.0 mL). This solution was added to the Ni(cod)2/1,5- hexadiene mixture, and the reaction was capped and stirred overnight to obtain an orange solution. The reaction vessel was opened, the reaction was filtered through Celite, and the filtrate was concentrated under reduced pressure. The crude product was dissolved in minimal amounts of hexanes and placed in the freezer (-30 °C) for 24 h. After the product precipitated, the remaining 96 solution was decanted, and the product was washed with cold hexanes. The product was dried under reduced pressure to yield 1d as bright, orange crystals. (0.38 g, 0.86 mmol, 48% yield). NMR spectra match values previously reported.125 (styrene)2Ni(IMes) (1e) was synthesized via a modified literature procedure:126 To a 100-mL round bottom flask equipped with a magnetic stir bar was added Ni(cod)2 (1.0 g, 3.6 mmol, 1.0 equiv), styrene (3.3 mL, 29 mmol, 8.0 equiv), and THF (32 mL). This red solution was stirred for 15 min at room temperature. In a separate 50-mL round bottom flask equipped with a stir bar was added IMes (1.1 g, 3.6 mmol, 1.0 equiv), and THF (32 mL). This solution was added dropwise to the Ni(cod)2 and styrene solution to afford an orange solution. This reaction was stirred for 2 h and then concentrated under reduced pressure to give an orange solid. The crude product was dissolved in a minimal amount of THF (5.0 mL) and filtered through Celite. The filtrate was concentrated under reduced pressure, solvated in minimal THF (3.0 mL) and hexanes (50 mL) was added to crash 1e out of solution. The product was collected via vacuum filtration and dried under reduced pressure to yield 1e as a bright orange powder (1.8 g, 3.2 mmol, 88% yield). NMR spectra match values previously reported.126 (allylether)Ni(IMes) (1f) To a round bottom flask equipped with a magnetic stir bar was added 1d (0.050 g, 0.11 mmol, 1.0 equiv) and toluene (0.5 mL). To this stirring solution, allyl ether (16 μL, 0.13 mmol, 1.2 equiv) was added. The reaction was stirred at room temperature for 12 h, 97 concentrated to leave ¼ of the solvent volume, and crystallized via slow vapor diffusion (toluene/hexanes). After pale yellow crystals formed, the solution was decanted away from the crystals, which were then washed with cold hexanes (0.032 g, 0.069 mmol, 63% yield). 1H NMR (500 MHz, C6D6, 298 K): δ 6.65 (s, 4H), 6.34 (s, 2H), 4.71 (dd, J = 12.0, 3.5 Hz, 2H), 3.08 (m, 2H), 2.16 (dd, J = 8.8, 1.2 Hz, 2H), 2.13 (d, 11.6 Hz, 2H), 2.10 (s, 12H), 2.02 (s, 6H), 1.82 (d, J = 12.5 Hz, 2H). 13C{1H} NMR (126 MHz, C6D6, 298 K): δ 203.6, 138.1, 137.8, 135.4, 129.1, 122.3, 70.9, 65.5, 41.1, 20.9, 18.3. IR (FT, KBr pellet) ν: 3155-2829 (w), 1488 (s), 1310 (s), 928 (s), 695 (m). ASAP/HRMS (m/z): [M+] calculated for C27H34N2NiO 460.2025, found 460.2041. b. Synthesis of Alkenes 4-(acetoxy)-benzaldehyde (S1) To an oven-dried Schlenk flask equipped with a magnetic stir bar was added 4-hydroxybenzaldehyde (1.23 g, 10.1 mmol, 1.0 equiv) and DCM (30 mL). The reaction was cooled with an ice/water bath before triethylamine (2.8 mL, 20 mmol, 2.0 equiv) was added slowly. DMAP (37 mg, 0.30 mmol, 0.030 equiv) was added portion-wise followed by dropwise addition of acetyl chloride (1.1 mL, 15 mmol, 1.5 equiv). The reaction was monitored by TLC (70/30 hexanes/EtOAc) and upon complete consumption of 4-hydroxybenzaldehyde, the reaction was opened to air and quenched with NaHCO3 (saturated aqueous, 50 mL). The aqueous layer was separated and extracted with Et2O (3 x 60 mL). The combined organic layers were washed with H2O (2 x 50 mL) and brine (2 x 50 mL). The organic layer was dried over Na2SO4, filtered, and concentrated under reduced pressure. The crude material was partially purified by column chromatography (silica, gradient 0-30% EtOAc/hexanes) to yield crude product as a white oil which was carried forward without further purification. NMR spectra match values previously reported.266 98 4-(2-propen-1-yloxy)benzaldehyde (S2) was synthesized following a literature procedure:267 To a two-neck round-bottom flask equipped with a magnetic stir bar was added 4- hydroxybenzaldehyde (1.53 g, 12.5 mmol, 1.0 equiv), acetone (65 mL), K2CO3 (6.91 g, 50.0 mmol, 4.0 equiv), and allyl bromide (2.2 mL, 25.4 mmol, 2.0 equiv). The reaction was equipped with a condenser and placed in a pre-heated oil bath at 70 °C to reflux. After 22 h, the reaction was cooled to room temperature and EtOAc (50 mL) and H2O (50 mL) were added to the reaction. This mixture was then transferred to a separatory funnel. The aqueous phase was separated and extracted with EtOAc (3 x 60 mL). The combined organic layers were dried over MgSO4, filtered and concentrated under reduced pressure to give the crude product. The crude material was purified by column chromatography (silica, gradient 0-5% EtOAc/hexanes) to give the product as a clear, colorless oil (1.00 g, 6.2 mmol, 50% yield). NMR spectra match values previously reported.268 Styrene derivatives were synthesized from the corresponding aldehydes via a modified literature procedure:269 To an oven-dried Schlenk flask equipped with a stir bar was added methyltriphenylphosphonium bromide and THF, which were stirred for 15 min at 0 °C (ice/water bath). To this mixture was added t-BuOK and stirred for 1 h at 0 °C. The corresponding aldehyde was added either neat or as a solution in THF to the reaction mixture dropwise. The reaction was taken out of the bath and allowed to warm to room temperature to stir for 24 h. After reaction completion determined by TLC, the reaction was quenched with NH4Cl (saturated aq.) and extracted with Et2O. The organic layer was separated, dried over MgSO4, filtered, and the resulting filtrate was concentrated under reduced pressure to obtain the crude product. Purification details are included below. 99 4-ethenyl-N,N-dimethylbenzenamine (2b) Synthesis details: methyltriphenylphosphonium bromide (2.8 g, 7.8 mmol, 1.6 equiv), t-BuOK (0.50 g, 4.5 mmol, 1.7 equiv), THF (50 mL), 4- (dimethylamino)benzaldehyde (0.73 g, 4.9 mmol, 1.0 equiv), THF (10 mL). Purification details: Column chromatography: silica, ethyl acetate/hexanes/TEA (3:96:1). Product is a pale-yellow oil (0.388 g, 2.64 mmol, 54% yield). NMR spectra match values previously reported.270 1-ethenyl-4-(trifluoromethyl)benzene (2g) Synthesis details: methyltriphenylphosphonium bromide (9.1 g, 25 mmol, 1.8 equiv), t-BuOK (1.6 g, 14 mmol, 1.0 equiv), THF (50 mL), 4- (trifluoromethyl)benzaldehyde (2.0 mL, 15 mmol, 1.0 equiv), THF (10 mL), quenched with NH4Cl (60 mL), extracted with Et2O (3 x 50 mL). Purification details: Column chromatography: silica, hexanes. Product is a colorless oil (0.640 g, 3.72 mmol, 25% yield). NMR spectra match values previously reported.271 4-acetoxystyrene (2k) Synthesis details: methyltriphenylphosphonium bromide (1.6 g, 4.6 mmol, 1.6 equiv), t-BuOK (0.52 g, 4.6 mmol, 1.6 equiv), THF (20 mL), 4- (acetoxy)-benzaldehyde (0.50 g, 3.0 mmol, 1.0 equiv). Purification details: Column chromatography: silica, gradient eluent (0- 15% EtOAc/hexanes). Product is a clear liquid (0.20 g, 1.2 mmol, 41% yield). NMR spectra match values previously reported.272 IR (ATR, neat) v: 1757 (s), 1504 (m), 1188 (s), 908 (m), 850 (m). 2-vinylthiophene (2l) 100 Synthesis details: methyltriphenylphosphonium bromide (4.59 g, 12.8 mmol, 1.2 equiv), t-BuOK (1.44 g, 12.8 mmol, 1.2 equiv), Et2O (75 mL), 2-thiophenecarboxaldehyde (1.03 mL, 11.0 mmol, 1.0 equiv). Purification details: Column chromatography: silica, hexanes. Product is a clear liquid (0.49 g, 4.4 mmol, 40% yield). NMR spectra match values previously reported.273,274 1-ethenyl-4-(2-propen-1-yloxy)benzene (2t) Synthesis details: methyltriphenylphosphonium bromide (1.65 g, 4.62 mmol, 1.5 equiv), t-BuOK (0.51 g, 4.5 mmol, 1.5 equiv), THF (20 mL), 4- (2-propen-1-yloxy)benzaldehyde (0.49 g, 3.0 mmol, 1.0 equiv). Purification details: Column chromatography: silica, gradient eluent (0-5% EtOAc/hexanes). Product is a clear liquid (0.27 g, 1.7 mmol, 57% yield). NMR spectra match values previously reported.275 c. Synthesis of Silanes Diaryl silanes were synthesized via modified literature procedure:276 To an oven-dried Schlenk flask equipped with a stir bar was added magnesium (2.5-9.0 equiv), iodine (cat.), and solvent. This mixture was cooled to 0 °C in an ice/water bath. A one-fourth portion of the aryl bromide was added slowly and this mixture was stirred for 10 min after a color change was observed. The remaining aryl bromide was added dropwise, and the reaction was equipped with a condenser and heated to reflux for 12 h. The reaction was removed from heat and allowed to cool to room temperature. In a separate oven-dried Schlenk flask, HSiCl3 or PhSiCl3 (1.0-1.3 equiv) and the reaction solvent were cooled to 0 °C in an ice/water bath. The Grignard solution was added dropwise to the chlorosilane solution via cannula. Upon complete addition, the flask was equipped with a condenser and heated to reflux and reacted overnight. The reaction was lifted from heat to 101 slowly cool to room temperature. The magnesium salts were filtered off with a swivel frit and the filtrate was transferred to another oven-dried Schlenk flask. The filtrate was added dropwise to an oven-dried Schlenk flask equipped with a stir bar containing LiAlH4 (1.0-2.1 equiv) and Et2O which was cooled to 0 °C in an ice/water bath. Upon complete addition, the reaction was allowed to warm to room temperature and stirred overnight. The reaction was slowly quenched with ice, acidified with 3 M HCl, and the crude product was extracted with Et2O. The combined organic layers were dried over MgSO4, the solids were filtered off, and the filtrate was concentrated to obtain crude product. Further purification details are included below. Di(4-methoxyphenyl)silane (3b) Synthesis details: 4-Bromoanisole (5.0 mL, 40 mmol, 2.0 equiv), THF (50 mL), magnesium (4.30 g, 177 mmol, 8.9 equiv), iodine (a chip), HSiCl3 (2.01 mL, 19.9 mmol, 1.0 equiv), THF (50 mL), LiAlH4 (0.907 g, 23.9 mmol, 1.2 equiv), Et2O (30 mL), quenched with ice (10 g), acidified with 3 M HCl (5 mL), extracted with Et2O (3 x 50 mL). Purification details: The compound was isolated by recrystallization in cyclohexane to yield a crystalline, white solid (0.66 g, 2.7 mmol, 14% yield). 1H NMR (600 MHz, CDCl3, 298 K): δ 7.52 (d, J = 8.5 Hz, 4H), 6.93 (d, J = 8.5 Hz, 4H), 4.89 (s, 1JH–Si = 197.5 Hz, 2H), 3.82 (s, 6H). 13C{1H} NMR (151 MHz, CDCl3, 298 K): δ 161.2, 137.3, 122.7, 114.1, 55.2. 29Si{1H} NMR (119 MHz, CDCl3, 298 K): δ -34.47 (s). IR (ATR, neat) ν: 2962 (m), 2141 (s, Si–H), 2117 (s, Si–H), 1593 (m), 1278 (s), 814 (s). ASAP/HRMS (m/z): [M+] calculated for C14H16O2Si 244.0920, found 244.0950. Di(4-methylphenyl)silane (3c) Synthesis details: 4-bromotoluene (4.0 mL, 33 mmol, 2.0 equiv), THF (60 mL), magnesium (3.52 g, 145 mmol, 9.0 equiv), iodine (a chip), HSiCl3 (1.64 mL, 16.2 mmol, 1.0 equiv), THF (35 mL), LiAlH4 (1.23 g, 32.4 mmol, 2.0 equiv), Et2O (30 mL), 102 quenched with ice (10 g), acidified with 3 M HCl (5 mL), extracted with Et2O (3 x 50 mL). Purification details: Column chromatography: silica gel, pentane to yield a colorless oil (0.862 g, 4.06 mmol, 25% yield). NMR spectra match values previously reported.276 Di(3-fluorophenyl)silane (3d) Synthesis details: 1-bromo-3-fluorobenzene (4.0 mL, 36 mmol, 2.0 equiv), THF (80 mL), magnesium (3.87 g, 159 mmol, 8.9 equiv), iodine (a chip), HSiCl3 (1.81 mL, 17.9 mmol, 1.0 equiv), THF (40 mL), LiAlH4 (0.81 g, 21 mmol, 1.2 equiv), Et2O (20 mL), quenched with ice (10 g), acidified with 3 M HCl (5 mL), extracted with Et2O (3 x 50 mL). Purification details: Column chromatography: silica gel, pentanes to a colorless oil (1.36 g, 6.18 mmol, 34% yield). 1H NMR (600 MHz, C6D6, 298 K): δ 7.14 (dd, J = 8.4, 2.0 Hz, 2H), 7.04 (d, J = 7.1 Hz, 2H), 6.87 (m, 2H), 6.79 (td, J = 8.7, 2.5 Hz, 2H), 4.80 (s, 1JH–Si = 203.8 Hz, 2H). 13C{1H} NMR (151 MHz, C6D6, 298 K): δ 163.6 (d, J = 248.8 Hz), 133.9 (d, J = 4.5 Hz), 131.5 (d, J = 3.2 Hz), 130.4 (d, J = 7.0 Hz), 122.2 (d, J = 19.1 Hz), 117.4 (d, J = 21.0 Hz). 19F NMR (471 Hz, C6D6, 298 K): δ -112.37 (td, J = 8.8, 5.2 Hz). 29Si{1H} NMR (199 MHz, C6D6, 298 K): δ -33.81 (s). IR (ATR, neat) ν: 3064-2879 (m), 2143 (s, Si–H), 1574 (s), 1217 (s), 825 (s). ASAP/HRMS (m/z): [M+] calculated for C12H10F2Si 220.0520, found 220.0526. 103 Di[4-(trifluoromethyl)phenyl]silane (3e) Synthesis details: 4-bromobenzotrifluoride (5.0 mL, 36 mmol, 1.9 equiv), Et2O (40 mL), magnesium (3.50 g, 146 mmol, 7.5 equiv), iodine (a chip), HSiCl3 (2.45 mL, 24.3 mmol, 1.3 equiv), Et2O (20 mL), LiAlH4 (0.74 g, 19.5 mmol, 1.0 equiv), Et2O (15 mL), quenched with ice (10 g), acidified with 3 M HCl (5 mL), extracted with Et2O (3 x 50 mL). Purification details: Column chromatography: silica gel, pentanes/Et2O (95:5), concentrated, and then distilled to yield a colorless oil (1.06 g, 3.31 mmol, 17% yield). 1H NMR (500 MHz, C6D6, 298 K): δ 7.31 (d, J = 7.8 Hz, 4H), 7.19 (d, J = 7.8 Hz, 4H), 4.76 (s, 1JH–Si = 204.8 Hz, 2H). 13C{1H} NMR (126 MHz, C6D6, 298 K): δ 136.2, 135.5, 132.4 (q, J = 32.2 Hz), 125.0 (q, J = 3.8 Hz), 124.7 (q, J = 272.5 Hz)*. *Note that the most upfield peak of this quartet (assigned to CF3) is obscured by the C6D6 peak. 19F NMR (471 Hz, C6D6, 298 K): δ -62.88 (s). 29Si{1H} NMR (99 MHz, C6D6, 298 K): δ -34.00 (s). IR (ATR, neat) ν: 2154 (m, Si–H), 1394 (m), 1321 (s), 1059 (s), 820 (s). ASAP/HRMS (m/z): [M+] calculated for C14H10F6Si 320.0456, found 320.0455. Di(3-methylphenyl)silane (3f) Synthesis details: 3-bromotoluene (4.5 mL, 37 mmol, 1.9 equiv), THF (60 mL), magnesium (4.0 g, 160 mmol, 9.0 equiv), iodine (a chip), HSiCl3 (1.9 mL, 19 mmol, 1.0 equiv), THF (40 mL), LiAlH4 (0.85 g, 22.4 mmol, 1.2 equiv), Et2O (40 mL), quenched with ice (10 g), acidified with 3 M HCl (5 mL), extracted with Et2O (3 x 50 mL). Purification details: Column chromatography: silica gel, pentane to yield a colorless oil (1.36 g, 6.40 mmol, 34% yield). NMR spectra match values previously reported.277 104 IR (ATR, neat) v: 3064-2877 (w), 2127 (s, Si–H), 1396 (w), 1120 (s), 823 (s). Di(2-methylphenyl)silane (3g) Synthesis details: 2-bromotoluene (4.0 mL, 33 mmol, 2.0 equiv), THF (45 mL), magnesium (3.59 g, 148 mmol, 8.9 equiv), iodine (a chip), HSiCl3 (1.68 mL, 16.6 mmol, 1.0 equiv), THF (30 mL), LiAlH4 (0.631 g, 16.6 mmol, 1.0 equiv), Et2O (20 mL), quenched with ice (10 g), acidified with 3 M HCl (5 mL), extracted with Et2O (3 x 50 mL). Purification details: Column chromatography: silica gel, cyclohexane to yield a colorless oil (1.13 g, 5.32 mmol, 32% yield). 1H NMR (600 MHz, CDCl3, 298 K): δ 7.51 (d, J = 7.3 Hz, 2H), 7.36 (t, J = 7.5 Hz, 2H), 7.23 (d, J = 7.5 Hz, 2H), 7.19 (t, J = 7.3 Hz, 2H), 5.00 (s, 1JH–Si = 198.2 Hz, 2H), 2.43 (s, 6H). 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 144.7, 137.1, 130.9, 130.5, 129.6, 125.4, 22.7. 29Si{1H} NMR (99 MHz, CDCl3, 298 K): δ -39.76 (s). IR (ATR, neat) ν: 3051-2858 (w), 2131 (s, Si–H), 1446 (m), 1132 (m), 847 (s). ASAP/HRMS (m/z): [M+] calculated for C14H16Si 212.1021, found 212.1011. Mesitylphenylsilane (3h) Synthesis details: 2-bromomesitylene (2.14 mL, 14.0 mmol, 1.0 equiv), THF (100 mL), magnesium (0.85 g, 35 mmol, 2.5 equiv), iodine (a chip), SiPhCl3 (2.24 mL, 14.0 mmol, 1.0 equiv), LiAlH4 (1.13 g, 29.8 mmol, 2.1 equiv), quenched with ice (10 g), acidified with 3 M HCl (5 mL), extracted with Et2O (3 x 100 mL). Purification details: Column chromatography: silica gel, hexanes to yield a colorless oil (1.36 g, 6.01 mmol, 43% yield). NMR matches previously reported values.278 105 Triaryl silanes were synthesized in accordance with a literature procedure.112 Purification details are included below. Tri[4-(methoxy)phenyl]silane (3k) Synthesis details: 4-bromoanisole (2.7 mL, 21 mmol, 3.0 equiv), Et2O (26 mL), magnesium (1.0 g, 42 mmol, 6.0 equiv), iodine (a chip), HSiCl3 (0.71 mL, 7.0 mmol, 1.0 equiv), quenched with 3M HCl (5 mL), extracted with Et2O (5 x 50 mL). Purification details: Column chromatography: silica gel, hexanes/Et2O (95:5) to give the product as a white solid (2.16 g, 6.15 mmol, 89% yield). NMR matches previously reported values.112 Tri[4-(trifluoromethyl)phenyl]silane (3m) Synthesis details: 4-bromobenzotrifluoride (4.0 mL, 29 mmol, 3.3 equiv), Et2O (40 mL), magnesium (2.79 g, 115 mmol, 13 equiv), iodine (a chip), HSiCl3 (0.88 mL, 8.7 mmol, 1.0 equiv), quenched with water (20 mL), extracted with Et2O (3 x 50 mL). Purification details: Column chromatography: silica gel, hexanes/Et2O (95:5) to give the product as a white solid (1.36 g, 2.93 mmol, 34% yield). NMR matches previously reported values.112 106 A.1.4. Evaluation of Nickel Complexes for Hydrosilylation In a nitrogen-filled glovebox, Ni complexes were added to a 1-dram vial equipped with a stir bar via stock solutions prepared by weighing out the complex, dissolving it in the appropriate volume of toluene using volumetric glassware, and distributing the stock solutions using a 250-µL syringe. 2a (10 µL, 0.088 mmol, 1.0 equiv) and 3a (16 µL, 0.088, 1.0 equiv) were added to each vial using a 25-µL syringe, separately. The vials were sealed with a Teflon-lined thermoset cap, removed from the glovebox, and placed on a pre-heated aluminum vial block at the appropriate temperature. After 4 h, the vial was quenched by cooling in a liquid N2 bath, opening to air, and durene or trimethoxybenzene was added to the reaction as a stock solution via a 250-µL syringe; the stock solution had been prepared by weighing out durene or trimethoxybenzene and dissolving in hexanes using volumetric glassware. After mixing, an aliquot (5 μL) of the reaction was removed using a 25-µL syringe and filtered with hexanes through Celite directly into a GC vial. The filtrate was analyzed by GC and/or GC-MS to assess reaction progress and selectivity (linear, l; branched, b). The product yield was determined by relative integration (by GC or GC-MS) of the product peaks and standard against a calibration curve. Yields reported are the average of at least two trials and the errors in yield are the standard deviation. Table A.1. Evaluation of the reactivity of nickel complexes. Entry Ni source Yield (%) Selectivity (l:b) 1 (dvtms)Ni(ITMe) (1a) 56 ± 8 1:2.0 2 (dvtms)Ni(IMes) (1b) 21 ± 6 1:1.5 3 (dvtms)Ni(IPr) (1c) 11.6 ± 0.2 1:1.2 4 (1,5-hexadiene)Ni(IMes) (1d) 29 ± 1 1:8.1 5 (styrene)2Ni(IMes) (1e) 49 ± 0 1:3.3 6 (allylether)Ni(IMes) (1f) 39a 1:0.8 7 (IMes)Ni(μ-H–SiPh2)2Ni(IMes) (1g) 31 ± 1 1:0.8 8 (IMes)Ni(μ-H–SiPh2)2Ni(IMes) (1g) 74 ± 2 b 1:0.9 aOnly one trial was carried out. bReaction carried out at 100 °C. A.1.4. Evaluation of Reaction Conditions for Hydrosilylation 107 In a nitrogen-filled glovebox, Ni complexes were added to a 1-dram vial equipped with a stir bar via stock solutions prepared by weighing out the complex, dissolving it in the appropriate volume of solvent using volumetric glassware, and distributing the stock solutions using a 250-µL syringe. For the reaction in Table S2, entry 2, IMes•HCl (0.0088 mmol, 0.050 equiv) and KOt-Bu (0.0089 mmol, 0.050 equiv) were weighed out directly into the appropriate vial before the addition of the Ni stock solution. Additional solvent was added using a disposable plastic syringe to bring the total reaction volume to the appropriate volume. 2a (10 µL, 0.088 mmol, 1.0 equiv) and 3a (16 µL, 0.088, 1.0 equiv) were added to each vial using a 25-µL syringe, separately. The vials were sealed with a Teflon-lined thermoset cap, removed from the glovebox and placed on a pre-heated aluminum vial block at the appropriate temperature. After 4 h, the vial was quenched by cooling in a liquid N2 bath, opening to air, and durene or trimethoxybenzene was added to the reaction as a stock solution via a 250-µL syringe; the stock solution had been prepared by weighing out durene or trimethoxybenzene and dissolving in hexanes using volumetric glassware. After mixing, an aliquot (5 μL) of the reaction was removed using a 25-µL syringe and filtered with hexanes through Celite directly into a GC vial. The filtrate was analyzed by GC and/or GC-MS to assess reaction progress and selectivity. The product yield was determined by relative integration (by GC or GC- MS) of the product peaks and standard against a calibration curve. Yields reported are the average of at least two trials and the errors in yield are the standard deviation. Table A.2. Evaluation of the reaction conditions. Entry [Ni] Deviation from standard conditions Yield (%) Selectivity (l:b) 1 Ni(cod)2 (5 mol %) None 77 ± 8 1:0.7 Addition of IMes•HCl (5 mol %) and 2 Ni(cod)2 (5 mol %) 67 ± 2 1:7.4 KOt-Bu (5 mol %) 3 No catalyst None n.d.a -- 4 1e (2.5 mol %) None 60 ± 10 1:3.0 5 1e (5 mol %) None 72 ± 5 1:4.0 6 1e (10 mol %) None 79 ± 4 1:6.8 7 1e (20 mol %) None 81 ± 7 1:6.8 108 8 1e (5 mol %) Hexanes used instead of toluene 70 ± 7 1:5.2 9 1e (5 mol %) 1,4-dioxane used instead of toluene 65 ± 5 1:4.9 10 1e (5 mol %) THF used instead of toluene 43.8 ± 0.9 1:2.3 11 1e (5 mol %) DMF used instead of toluene 31 ± 9 1:1.6 12 1e (5 mol %) ACN used instead of toluene 31 ± 2 1:0.4 13 1e (5 mol %) DCM used instead of toluene 48.9 ± 3 1:0.6 14 1e (5 mol %) 25 °C instead of 70 °C 2.3 ± 0.3 1:2.3 15 1e (5 mol %) 60 °C instead of 70 °C 38 ± 5 1:1.4 16 1e (5 mol %) 80 °C instead of 70 °C 76 ± 5 1:8.6 17 1e (5 mol %) 90 °C instead of 70 °C 85.0 ± 0.5 1:11 18b 1e (5 mol %) 100 °C instead of 70 °C 95 1:>99 19 1d (5 mol %) 100 °C instead of 70 °C 93 ± 1 1:55 an.d., not detected. bOnly one trial was carried out. A.1.5. Evaluation of the Substrate Scope for Hydrosilylation a. General Procedures General procedure A (GP-A): In a nitrogen-filled glovebox, a 4-dram scintillation vial was charged with 1e (28.6 mg, 0.0500 mmol, 0.050 equiv) and toluene (4.6 mL). The alkene substrate (1.0 mmol, 1.0 equiv) was added to this mixture followed by the silane substrate (1.1 mmol, 1.1 equiv) using a 250-µL syringe. The vial was sealed with a Teflon-lined thermoset cap, brought out of the glovebox, and heated at 100 °C on a pre-heated vial block for 4 h. The reaction was quenched by cooling it in a liquid N2 bath and then it was allowed to warm to room temperature. An aliquot (~5 μL) was removed for analysis by GC-MS, and the reaction was then concentrated under reduced pressure to yield the crude product. The product was purified as described below for each substrate. General procedure B (GP-B): Followed GP-A except catalyst 1d (23 mg, 0.050 mmol, 0.050 equiv) was used instead of 1e. General procedure C (GP-C): In a nitrogen-filled glovebox, a 2-dram scintillation vial equipped with a stir bar was charged with 1e (28.6 mg, 0.0500 mmol, 0.050 equiv), 2a (120 µL, 1.0 mmol, 1.0 equiv), and hexanes (4.6 mL). The vial was sealed with a septum cap and brought out of the glovebox, injected with the silane substrate (1.25 mmol, 1.25 equiv) using a disposable 1-mL syringe, and heated at 100 °C in a pre-heated oil bath for 24 h. The reaction was quenched by 109 cooling it in a liquid N2 bath and then it was allowed to warm to room temperature. An aliquot (~5 μL) was removed for analysis by GC-MS. The product was purified as described below for each substrate. General procedure D (GP-D): In a nitrogen-filled glovebox, a 1-dram scintillation vial equipped with a stir bar was charged with Ni(cod)2 (14 mg, 0.050 mmol, 0.050 equiv), ITMe (6.2 mg, 0.050 mmol, 0.050 equiv), and toluene (0.42 mL). The reaction was stirred for 5 min and then 2a (120 µL, 1.0 mmol, 1.0 equiv, unless stated otherwise in the table below) was added via a 250-µL syringe, and the reaction was stirred for an additional 5 min. Finally, the silane substrate (see amount in table below) was added directly as a solid or using a 250-µL syringe or a disposable 1- mL syringe. The vial was sealed with a Teflon-lined thermoset cap, brought out of the glovebox, and heated at 100 °C on a pre-heated aluminum vial block for 24 h. The reaction was quenched by cooling it in a liquid N2 bath and then it was allowed to warm to room temperature. An aliquot (~5 μL) was removed for analysis by GC, and the reaction was then concentrated under reduced pressure to yield the crude product. The product was purified as described below for each substrate. General procedure E (GP-E): In a nitrogen-filled glovebox, a 1-dram scintillation vial equipped with a stir bar was charged with Ni(cod)2 (14 mg, 0.050 mmol, 0.050 equiv), ITMe (6.2 mg, 0.050 mmol, 0.050 equiv), and toluene (0.42 mL). The reaction was stirred for 5 min and then 2a (115 µL, 1.0 mmol, 1.0 equiv) was added via 250-µL syringe, and the reaction was stirred for an additional 5 min. The vial was sealed with a septum cap, brought out of the glovebox, and injected with triethoxysilane 3p (0.37 mL, 2.0 mmol, 2.0 equiv) using a disposable 1-mL syringe, and heated at 100 °C in a pre-heated oil bath for 24 h. The reaction was quenched by cooling it in a liquid N2 bath and then it was allowed to warm to room temperature. An aliquot (~5 μL) was removed for analysis by GC, and the reaction was then concentrated under reduced pressure to yield the crude product. The product was purified as described below for each substrate. b. Successful Substrates (1-Phenylethyl)diphenylsilane (4aa) Synthesis details: GP-A, styrene (2a), H2SiPh2 (3a). Selectivity before purification: 1:>99 (l/b) measured by GC-MS. 110 Purification details: Column chromatography: silica, benzene/hexanes (2:98) to give the product as a clear oil (0.248 mg, 0.860 mmol, 86% yield, l/b = 1:>99). NMR spectra match values previously reported.279 1H NMR (500 MHz, CD3CN, 298 K): δ 7.59 (d, J = 7.3 Hz, 2H), 7.44-7.34 (ms, 6H), 7.29 (t, J = 7.2 Hz, 2H), 7.17 (t, J = 7.6 Hz, 2H), 7.09-7.06 (ms, 3H), 4.79 (d, J = 4.2 Hz, 1JH–Si = 196.1 Hz, 1H), 2.94 (qd, J = 7.4, 4.2 Hz, 1H), 1.43 (d, J = 7.4 Hz, 3H). 13C{1H} NMR (126 MHz, CD3CN, 298 K): δ 145.6, 136.4, 136.3, 134.3, 134.2, 130.9, 130.7, 129.2, 129.1, 128.9, 128.7, 125.9, 27.2, 17.2. 29Si{1H} NMR (99 MHz, CD3CN, 298 K): δ -7.42 (s). [1-(4-Dimethylaminophenyl)ethyl]diphenylsilane (4ba) Synthesis details: GP-A, 4-dimethylaminostyrene (2b), H2SiPh2 (3a). Selectivity before purification: 1:>99 (l/b) measured by GC-MS. Purification details: Column chromatography: silica, Et2O/hexanes (5:95) to give the product as an amber oil. (0.26 g, 0.77 mmol, 77% yield, l/b = 1:>99).280 1H NMR (500 MHz, CDCl3, 298 K): δ 7.52 (d, J = 7.9 Hz, 2H), 7.41- 7.32 (m, 6H), 7.26 (m, 2H), 6.90 (d, J = 8.4 Hz, 2H), 6.62 (d, J = 8.4 Hz, 2H), 4.83 (d, J = 3.2 Hz, 1JH–Si = 196.2 Hz, 1H), 2.88 (s, 6H), 2.73 (qd, J = 7.5, 3.3 Hz, 1H), 1.42 (d, J = 7.5 Hz, 3H). 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 148.6, 135.9, 135.8, 133.73, 133.67, 132.6, 129.7, 129.5, 128.4, 128.0, 127.8, 113.2, 41.1, 25.6, 17.1. 29Si{1H} NMR (99 MHz, CDCl3, 298 K): δ -9.24 (s). IR (ATR, neat) ν: 3066-2804 (w), 2102 (s, Si–H), 1518 (s), 1105 (m), 696 (s). [1-(4-Methoxyphenyl)ethyl]diphenylsilane (4ca) Synthesis details: GP-A, 4-methoxystyrene (2c), H2SiPh2 (3a). Selectivity before purification: 1:43 (l/b) measured by GC-MS. Purification details: Column chromatography: silica, methyl-t-butyl ether/cyclohexane (5:95) to give the product as a white solid (0.270 g, 0.85 mmol, 85% yield, l/b = 1:33). NMR spectra match values previously reported.92,279 111 The major product isolated is the branched isomer, and the linear isomer is seen in the NMR spectra as well. The ratio of these isomers was determined by relative integrations of the benzylic C–H positions and was found to be 1:33 (l/b). The branched product is fully characterized below, and the peaks visible and clearly assignable to the linear isomer are given directly following the NMR characterization of the branched product. Branched product: 1H NMR (500 MHz, CD3CN, 298 K): δ 7.58 (d, J = 7.5 Hz, 2H), 7.45- 7.35 (ms, 6H), 7.29 (t, J = 7.4 Hz, 2H), 7.01 (d, J = 8.5 Hz, 2H), 6.75 (d, J = 8.5 Hz, 2H), 4.79 (d, J = 4.1 Hz, 1JH–Si = 195.1 Hz, 1H), 3.71 (s, 3H), 2.87 (qd, J = 7.5, 4.2 Hz, 1H), 1.39 (d, J = 7.5 Hz, 3H). 13C{1H} NMR (126 MHz, CD3CN, 298 K): δ 158.3, 137.4, 136.4, 136.3, 134.6, 134.4, 130.8, 130.7, 129.6, 129.1, 128.9, 114.6, 55.8, 26.1, 17.5. 29Si{1H} NMR (99 MHz, CD3CN, 298 K): δ -7.65 (s). Linear product: 1H NMR (500 MHz, CD3CN, 298 K): δ 7.11 (d, J = 8.4 Hz, 0.07H), 6.81 (d, J = 8.4 Hz, 0.08H), 4.82 (t, J = 3.9 Hz, 0.03 H), 3.74 (s, 0.09H), 2.68 (m, 0.06 H). 29Si{1H} NMR (99 MHz, CD3CN, 298 K): δ -7.42 (s). [1-(4-tert-Butylphenyl)ethyl]diphenylsilane (4da) Synthesis details: GP-A, 4-tert-butylstyrene (2d), H2SiPh2 (3a). Selectivity before purification: 1:>99 (l/b) measured by GC-MS. Purification details: Column chromatography: silica, benzene/hexanes (gradient 0:100 to 5:95) to give the product as a clear oil (0.318 g, 0.923 mmol, 92% yield, l/b = 1:>99). NMR spectra match values previously reported.77 1H NMR (500 MHz, CD3CN, 298 K): δ 7.58 (d, J = 7.9 Hz, 2H), 7.45-7.35 (ms, 6H), 7.29 (t, J = 7.3 Hz, 2H), 7.23 (d, J = 8.2 Hz, 112 2H), 7.04 (d, J = 8.2 Hz, 2H), 4.80 (d, J = 4.1 Hz, 1JH–Si = 195.5 Hz, 1H), 2.91 (qd, J = 7.5, 4.2 Hz, 1H), 1.41 (d, J = 7.5 Hz, 3H), 1.26 (s, 9H). 13C{1H} NMR (126 MHz, CD3CN, 298 K): δ 148.8, 142.5, 136.4, 136.3, 134.5, 134.4, 130.8, 130.7, 129.1, 128.9, 128.4, 126.1, 34.9, 31.6, 26.5, 17.4. 29Si{1H} NMR (99 MHz, CD3CN, 298 K): δ -7.88 (s). [1-(4-Methylphenyl)ethyl]diphenylsilane (4ea) Synthesis details: GP-A, 4-methylstyrene (2e), H2SiPh2 (3a). Selectivity before purification: 1:55 (l/b) measured by GC-MS. Purification details: Column chromatography: silica, benzene/hexanes (gradient 0:100 to 5:95) to give the product as a clear oil (0.238 g, 0.787 mmol, 79% yield, l/b = 1:>99). NMR spectra match values previously reported.279 1H NMR (500 MHz, CD3CN, 298 K): δ 7.61 (d, J = 7.5 Hz, 2H), 7.47 (m, 1H), 7.41 (t, J = 7.5 Hz, 2H), 7.36-7.32 (ms, 3H), 7.25 (t, J = 7.4 Hz, 2H), 7.10 (m, 2H), 7.04 (d, J = 7.3 Hz, 1H), 6.99 (t, J = 7.3 Hz, 1H), 4.79 (d, J = 4.1 Hz, 1JH–Si = 195.6 Hz, 1H), 3.09 (qd, J = 7.3, 4.1 Hz, 1H), 2.11 (s, 3H), 1.40 (d, J = 7.4 Hz, 3H). 13C{1H} NMR (126 MHz, CD3CN, 298 K): δ 142.5, 136.3, 136.2, 135.3, 134.6, 134.4, 130.8, 130.7, 129.8, 129.1, 128.9, 128.6, 26.6, 20.9, 17.4. 29Si{1H} NMR (99 MHz, CD3CN, 298 K): δ -8.54 (s). [1-(4-Fluorophenyl)ethyl]diphenylsilane (4fa) Synthesis details: GP-A, 4-fluorostyrene (2f), H2SiPh2 (3a). Selectivity before purification: 1:33 (l/b) measured by GC-MS. Purification details: Column chromatography: silica, benzene/hexanes (5:95) to give the product as a clear oil (0.209 g, 113 0.690 mmol, 69% yield, l/b = 1:42). NMR spectra match values previously reported.120,77 The major product isolated is the branched isomer, and the linear isomer is seen in the NMR spectra as well. The ratio of these isomers was determined by relative integrations of the benzylic C–H positions and was found to be 1:42 (l/b). The branched product is fully characterized below, and the peaks visible and clearly assignable to the linear isomer are given directly following the NMR characterization of the branched product. Branched product: 1H NMR (500 MHz, CD3CN, 298 K): δ 7.59 (d, J = 7.5 Hz, 2H), 7.45 (m, 1H), 7.41 (d, J = 7.3 Hz, 4H), 7.37 (m, 1H), 7.30 (t, J = 7.3 Hz, 2H), 7.06 (dd, J = 8.4, 5.8 Hz, 2H), 6.91 (t, J = 8.8 Hz, 2H), 4.79 (d, J = 4.1 Hz, 1JH–Si = 196.2 Hz, 1H), 2.95 (qd, J = 7.5, 4.1 Hz, 1H), 1.41 (d, J = 7.6 Hz, 3H). 13C{1H} NMR (126 MHz, CD3CN, 298 K): δ 161.5 (d, J = 240.8 Hz), 141.6 (d, J = 3.2 Hz), 136.4, 136.3, 134.1, 134.0, 130.9, 130.8, 130.1 (d, J = 7.7 Hz), 129.1, 128.9, 115.7 (d, J = 21.2 Hz), 26.5, 17.3. 19F NMR (471 MHz, CD3CN, 298 K): δ -120.36 (m). 29Si{1H} NMR (99 MHz, CD3CN, 298 K): δ -7.36 (s). Linear product: 1H NMR (500 MHz, CD3CN, 298 K): δ 7.17 (m, 0.24H), 7.10 (m, 0.28H), 4.80 2.72 (m, 0.06H). [1-(4-(Trifluoromethyl)phenyl)ethyl]diphenylsilane (4ga) Synthesis details: GP-A, 4-(trifluoromethyl)styrene (2g), H2SiPh2 (3a). Selectivity before purification: 1:78 (l/b) measured by GC-MS. 114 Purification details: Column chromatography: silica, hexanes to give the product as a clear oil (0.242 g, 0.679 mmol, 68% yield, l/b = 1:12). NMR spectra match values previously reported.280 The major product isolated is the branched isomer, and the linear isomer is seen in the NMR spectra as well. The ratio of these isomers was determined by relative integrations of the benzylic C–H positions and was found to be 1:12 (l/b). The branched product is fully characterized below, and the peaks visible and clearly assignable to the linear isomer are given directly following the NMR characterization of the branched product. IR (ATR, neat) ν: 3069-2843 (w), 2120 (s, Si–H), 1428 (m), 1322 (s), 695 (s). Branched product: 1H NMR (500 MHz, CD3CN, 298 K): δ 7.59 (d, J = 7.6 Hz, 2H), 7.46 (t, J = 7.2 Hz, 3H), 7.42-7.37 (ms, 5H), 7.30 (t, J = 7.5 Hz, 2H), 7.22 (d, J = 8.0 Hz, 2H), 4.79 (d, J = 4.0 Hz, 1JH–Si = 197.5 Hz, 1H), 3.07 (qd, J = 7.5, 4.0 Hz, 1H), 1.45 (d, J = 7.5 Hz, 3H) 13C{1H} NMR (126 MHz, CD3CN, 298 K): δ 150.8, 136.4, 136.2, 133.6, 133.5, 131.1, 130.9, 129.2, 129.1, 129.0, 127.3 (q, J = 32.0 Hz), 125.9 (q, J = 3.8 Hz), 125.6 (q, J = 270.9 Hz)*, 27.6, 16.6. *Note that the most downfield peak of this quartet (assigned to a CF3) is obscured by the product peak at 128.8 ppm. 19F NMR (471 MHz, CD3CN, 298 K): δ -62.61 (s). 29Si{1H} NMR (99 MHz, CD3CN, 298 K): δ -6.99 (s). Linear product: 1H NMR (500 MHz, CD3CN, 298 K): δ 7.56 (m), 4.83 (t, J = 3.8 Hz, 0.09H), 2.81 (m, 0.18) 19F NMR (471 MHz, CD3CN, 298 K): δ -62.71 (s). [1-(2-Methylphenyl)ethyl]diphenylsilane (4ha) 115 Synthesis details: GP-B, 2-methylstyrene (2h), H2SiPh2 (3a). Selectivity before purification: 1:26 (l/b) measured by GC. Purification details: Column chromatography: silica, benzene/hexanes (gradient 0:100 to 5:95) to give the product as a clear oil (0.266 g, 0.880 mmol, 88% yield, l/b = 1:26). NMR spectra match values previously reported.280 1H NMR (600 MHz, CDCl3, 298 K): δ 7.61 (d, J = 7.9 Hz, 2H), 7.49 (t, J = 7.5 Hz, 1H), 7.44 (t, J = 7.6 Hz, 2H), 7.40-7.36 (ms, 3H), 7.30 (t, J = 7.4 Hz, 2H), 7.19 (t, J = 7.3 Hz, 1H), 7.13-7.08 (m, 3H), 4.88 (d, J = 3.3 Hz, 1JH–Si = 197.7 Hz, 1H), 3.08 (qd, J = 7.4, 3.3 Hz, 1H), 2.14 (s, 3H), 1.51 (d, J = 7.4 Hz, 3H). 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 143.0, 136.0, 135.4, 135.3, 133.5, 133.0, 130.2, 129.9, 129.7, 128.1, 127.8, 126.9, 126.2, 124.9, 22.1, 20.2, 16.7. 29Si{1H} NMR (99 MHz, CDCl3, 298 K): δ -9.70 (s). IR (ATR, neat) ν: 3068-2061 (w), 2123 (s, Si–H), 1427 (s), 1106 (s), 796 (s). [1-(2-Naphthyl)ethyl]diphenylsilane (4ia) Synthesis details: GP-A, 2-vinylnapthylene (2i), H2SiPh2 (3a). Selectivity before purification: 1:55 (l/b) measured by GC. Purification details: Column chromatography: silica, benzene/pentane (2:98) to give the product as a clear oil (0.296 mg, 0.873 mmol, 87% yield, l/b = 1:21). NMR spectra match values previously reported for the branched product.279 The major product isolated is the branched isomer, and the linear isomer is seen in the NMR spectra as well. The ratio of these isomers was determined by relative integrations of the benzylic C–H positions and was found to be 1:21 (l/b). The branched product is fully 116 characterized below, and the peaks visible and clearly assignable to the linear isomer are given directly following the NMR characterization of the branched product. Branched product: 1H NMR (500 MHz, CD3CN, 298 K): δ 7.78 (d, J = 7.8 Hz, 1H), 7.68 (d, J = 8.5 Hz, 2H), 7.61 (d, J = 7.5 Hz, 2H), 7.53 (s, 1H), 7.46-7.37 (ms, 7H), 7.33 (m, 1H), 7.27-7.24 (ms, 3H), 4.87 (d, J = 4.1 Hz, 1JH– Si = 196.2 Hz, 1H), 3.12 (qd, J = 7.5, 4.1 Hz, 1H), 1.53 (d, J = 7.5 Hz, 3H). 13C{1H} NMR (126 MHz, CD3CN, 298 K): δ 143.4, 136.4, 136.3, 134.7, 134.2, 134.1, 132.5, 130.9, 130.7, 129.1, 128.9, 128.4 (2 signals), 128.1, 128.1, 126.9, 126.1, 125.9, 27.5, 17.1. 29Si{1H} NMR (99 MHz, CD3CN, 298 K): δ -7.51 (s). Linear product: 1H NMR (500 MHz, CD3CN, 298 K): δ 2.91 (m, 0.10H). [1-Phenylpropyl]diphenylsilane (4ja) Synthesis details: GP-B, Trans-β-methylstyrene (2j), H2SiPh2 (3a). Selectivity before purification: 1:>99 (l/b) measured by GC. Purification details: Column chromatography: silica, benzene/hexanes (gradient 0:100 to 5:95) to give the product as a clear oil (0.215 g, 0.711 mmol, 71% yield, l/b = 1:>99). NMR spectra match values previously reported.15,77 1H NMR (500 MHz, CD3CN, 298 K): δ 7.60 (d, J = 7.6 Hz, 2H), 7.46- 7.38 (ms, 5H), 7.34 (t, J = 7.3 Hz, 1H), 7.26 (t, J = 7.4 Hz, 2H), 7.18 (t, J = 7.5 Hz, 2H), 7.08 (m, 3H), 4.83 (d, J = 4.4 Hz, 1JH–Si = 195.4 Hz, 1H), 2.71 (dt, J = 10.6, 4.6 Hz, 1H), 1.87 (m, 2H), 0.81 (t, J = 7.2 Hz, 3H). 117 13C{1H} NMR (126 MHz, CD3CN, 298 K): δ 143.4, 136.4, 136.2, 134.6, 134.3, 130.8, 130.6, 129.5, 129.2, 129.1, 128.8, 126.0, 36.1, 25.3, 14.2. 29Si{1H} NMR (99 MHz, CD3CN, 298 K): δ -9.35 (s). [1-(4-Acetoxyphenyl)ethyl]diphenylsilane (4ka) Synthesis details: GP-A, 4-acetoxystyrene (2k), H2SiPh2 (3a). Selectivity before purification: 1:51 (l/b) measured by GC. Purification details: Column chromatography: silica, EtOAc/hexanes (5:95) to give the product as a colorless oil. (0.204 g, 0.589 mmol, 59% yield, l/b = 1:9.6). NMR spectra for the branched isomer match values previously reported.120 The major product isolated is the branched isomer, and the linear isomer is seen in the NMR spectra as well. The ratio of these isomers was determined by relative integrations of the benzylic C–H positions and was found to be 1:9.6 (l/b). The branched product is fully characterized below, and the peaks visible and clearly assignable to the linear isomer are given directly following the NMR characterization of the branched product. Branched product: 1H NMR (500 MHz, CD3CN, 298 K): δ 7.59 (m, 2H), 7.46-7.36 (ms, 6H), 7.30 (t, J = 7.3 Hz, 2H), 7.09 (d, J = 8.6 Hz, 2H), 6.89 (d, J = 8.6 Hz, 2H), 4.78 (d, J = 4.1 Hz, 1JH–Si = 196.2 Hz, 1H), 2.97 (qd, J = 7.5, 4.1 Hz, 1H), 2.20 (s, 3H) 1.42 (d, J = 7.5 Hz, 3H). 13C{1H} NMR (126 MHz, CD3CN, 298 K): δ 170.48, 149.3, 143.1, 136.4, 136.3, 134.1, 134.0 130.9, 130.8, 129.4, 129.1, 128.9, 122.4, 26.7, 21.3, 17.3. 29Si{1H} NMR (99 MHz, CD3CN, 298 K): δ -7.45 (s). Linear product: 118 1H NMR (500 MHz, CD3CN, 298 K): δ 7.22 (d, J = 8.4 Hz, 0.25H), 6.97 (d, J = 8.4 Hz, 0.23H), 4.83 (t, J = 3.7 Hz, 0.12H), 2.74 (m, 0.24H) 2.22 (s, 0.28H). 13C{1H} NMR (126 MHz, CD3CN, 298 K): 170.55, 150.0, 142.9, 136.0, 135.1, 129.8, 129.2, 122.6, 30.6, 26.3, 14.8. 29Si{1H} NMR (99 MHz, CD3CN, 298 K): δ -13.86 (s). [1-(2-Thiophenyl)ethyl]diphenylsilane (4la) Synthesis details: GP-B, 2-vinylthiophene (2l), H2SiPh2 (3a), reaction time of 24 h. Selectivity before purification: 1:13 (l/b) measured by GC. Purification details: Column chromatography: silica, hexanes to give the product as colorless oil. (0.219 g, 0.744 mmol, 74% yield, l/b = 1:6.7). NMR spectra for the branched isomer match values previously reported.77 The major product isolated is the branched isomer, and the linear isomer is seen in the NMR spectra as well. The ratio of these isomers determined by relative integrations of the benzylic C–H positions and was found to be 1:6.7 (l/b). The branched product is fully characterized below, and the peaks visible and clearly assignable to the linear isomer are given directly following the NMR characterization of the branched product. IR (ATR, neat) ν: 3069-2865 (w), 2117 (s, Si–H), 1427 (s), 1110 (s), 686 (s). ASAP/HRMS (m/z): [M+] calculated for C18H18SSi 294.0898, found 294.0885. Branched product: 1H NMR (500 MHz, CDCl3, 298 K): δ 7.58-7.56 (ms, 2H), 7.46-7.43 (ms, 3H), 7.42-7.37 (ms, 3H), 7.33 (m, 2H), 7.03 (dd, J = 5.1 Hz, 1.0 119 Hz, 1H), 6.88 (dd, J = 5.1, 3.5 Hz, 1H), 6.61 (d, J = 3.5 Hz, 1H), 4.94 (d, J = 3.3 Hz, 1JH–Si = 199.1 Hz, 1H) 3.15 (qd, J = 7.5, 3.3 Hz, 1H) 1.53 (d, J = 7.5 Hz, 3H). 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 148.3, 135.8, 135.7, 132.9, 132.7, 130.0, 129.92, 128.1, 128.0, 126.9, 122.9, 121.9, 22.4, 18.2 29Si{1H} NMR (99 MHz, CDCl3, 298 K): δ -9.12 (s). Linear product: 1H NMR (500 MHz, CDCl3, 298 K): δ 7.60 (m, 0.88H), 7.12 (dd, J = 5.1, 1.1 Hz, 0.15H), 6.91 (dd, J = 5.1, 3.4 Hz, 0.16H), 6.80 (m, 0.15H), 4.93 (m), 3.00 (m, 0.31H), 1.63 (m, 0.31H). 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 147.9, 135.3, 133.9, 129.88, 128.2, 126.80, 123.6, 123.0, 25.0, 15.0. 29Si{1H} NMR (99 MHz, CDCl3, 298 K): δ -14.44 (s). (3,3-Dimethyl-1-butyl)diphenylsilane (4ma) Synthesis details: GP-A, 3,3-dimethyl-1-butene (2m), H2SiPh2 (3a). Selectivity before purification: >99:1 (l/b) measured by GC. Purification details: Column chromatography: silica, benzene/hexanes (5:95) to give the product as a clear oil (0.215 g, 0.800 mmol, 80% yield, l/b = >99:1). NMR spectra match values previously reported.281 1H NMR (500 MHz, CD3CN, 298 K): δ 7.58 (d, J = 7.7 Hz, 4H), 7.43- 7.37 (ms, 6H), 4.78 (t, J = 3.8 Hz, 1JH–Si = 191.2 Hz, 1H), 1.30 (m, 2H), 1.14 (m, 2H), 0.87 (s, 9H). 13C{1H} NMR (126 MHz, CD3CN, 298 K): δ 135.9, 135.6, 130.6, 129.1, 39.2, 31.8, 29.0, 6.9. 29Si{1H} NMR (99 MHz, CD3CN, 298 K): δ -11.77 (s). 120 IR (ATR, neat) ν: 3068-2840 (w), 2114 (s, Si–H), 1427 (s), 1115 (s), 694 (s). ASAP/HRMS (m/z): [M+] calculated for C18H24Si 268.1647, found 268.1624. (2-cyclohexylethyl)diphenylsilane (4na) Synthesis details: GP-A, vinylcyclohexane (2n), H2SiPh2 (3a). Selectivity before purification: >99:1 (l/b) measured by GC. Purification details: Column chromatography: silica, benzene/hexanes (5:95) to give the product as a clear oil (0.162 g, 0.550 mmol, 55% yield, l/b = 20:1). NMR spectra match values previously reported.75 The major product isolated is the linear isomer, and the branched isomer is seen in the NMR spectra as well. The ratio of these isomers determined by relative integrations of Si–H and was found to be 20:1 (l/b). The linear product is fully characterized below, and the peaks visible and clearly assignable to the branched isomer are given directly following the NMR characterization of the linear product. IR (ATR, neat) v: 3067-2848 (w), 2110 (s, Si–H), 1427 (s), 1116 (s), 695 (s). Linear product: 1H NMR (500 MHz, CDCl3, 298 K): δ 7.58 (d, J = 7.2 Hz, 4H), 7.43- 7.37 (ms, 6H), 4.86 (t, J = 3.7 Hz, 1JH–Si = 192.3 Hz, 1H), 1.77-1.65 (ms, 5H), 1.37 (m, 2H), 1.23-1.13 (ms, 6H), 0.87 (q, J = 12.0 Hz, 2H). 13C{1H} NMR (126 MHz, CD3CN, 298 K): δ 135.3, 134.9, 129.6, 128.1, 40.6, 33.1, 32.0, 26.9, 26.5, 9.3. 29Si{1H} NMR (99 MHz, CDCl3, 298 K): δ -13.08 (s). Branched product: 121 1H NMR (500 MHz, CDCl3, 298 K): δ 7.62 (d, J = 7.3 Hz, 0.08H), 4.90 (d, J = 3.5 Hz, 0.05H). (1-decyl)diphenylsilane (4oa) Synthesis details: GP-A, 1-decene (2o), H2SiPh2 (3a). Selectivity before purification: 11:1 (l/b) measured by GC. Purification details: Column chromatography: silica, benzene/hexanes (5:95) to give the product as a clear oil (0.11 g, 0.34 mmol, 34% yield, l/b = 8.3:1). NMR spectra match values previously reported.75 The major product isolated is the linear isomer, and the branched isomer is seen in the NMR spectra as well. The ratio of these isomers determined by relative integrations of the Si–H positions and was found to be 8.3:1 (l/b). The linear product is fully characterized below, and the peaks visible and clearly assignable to the branched isomer are given directly following the NMR characterization of the linear product. IR (ATR, neat) v: 3067-2851 (w), 2113 (s, Si–H), 1428 (s), 1115 (s), 695 (s). Linear product: 1H NMR (500 MHz, CDCl3, 298 K): δ 7.56 (d, J = 7.2 Hz, 4H), 7.40- 7.34 (ms, 6H), 4.85 (t, J = 3.7 Hz, 1JH–Si = 192.3 Hz, 1H), 1.46 (m, 2H), 1.35 (m, 2H), 1.30-1.23 (ms, 12H), 1.14 (m, 2H), 0.88 (t, J = 7.1 Hz, 3H). 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 135.3, 134.9, 129.6, 128.1, 33.3, 32.1, 29.8, 29.7, 29.5, 29.4, 24.6, 22.9, 14.3, 12.3. 29Si{1H} NMR (99 MHz, CDCl3, 298 K): δ -13.74 (s). Branched product: 122 1H NMR (500 MHz, CDCl3, 298 K): δ 7.59, 7.40, 4.74 (d, J = 3.0 Hz, 0.12H), 1.08 (0.5H), 0.97 (0.5H), 0.90 (0.22H). Benzyloxytriphenylsilane (4pl) Synthesis details: GP-D, benzaldehyde (2p), HSiPh3 (3l). Purification details: Hexanes (5.0 mL) was added to the crude reaction mixture and this mixture was filtered through celite to remove all solids. The filtrate was concentrated, dissolved in minimal hexanes (1.0 mL) and allowed to crystallize overnight in the freezer (-20 °C). The resulting solution was decanted away from the solids, which were then dried under vacuum to give the product as a white solid (0.343 g, 0.937 mmol, 94% yield). NMR spectra match values previously reported.282 1H NMR (500 MHz, CDCl3, 298 K): δ 7.82-7.80 (ms, 6H), 7.57-7.54 (m, 3H), 7.52-7.47 (ms, 8H), 7.43 (t, J = 7.5 Hz, 2H), 7.36 (t, J = 7.3 Hz, 1H), 5.04 (s, 2H). 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 140.7, 135.6, 134.1, 130.2, 128.4, 128.1, 127.2, 126.5, 65.7. 29Si{1H} NMR (99 MHz, CDCl3, 298 K): δ -11.88 (s). IR (ATR, neat) v: 3064-2825 (w), 1586 (w), 1426 (s), 1114 (s), 695 (s). ASAP/HRMS (m/z): [M+] calculated for C25H22OSi 366.1440, found 366.1420. (1-Phenylethoxy)triphenylsilane (4ql) Synthesis details: GP-A, acetophenone (2q), HSiPh3 (3l), reaction time of 24 h. Purification details: Column chromatography: silica, Et2O/hexanes (5:95) to give the product as a white solid (0.379 g, 0.996 mmol, 99.6% yield). NMR spectra match values previously reported.283 123 1H NMR (500 MHz, CD3CN, 298 K): δ 7.57 (d, J = 7.4 Hz, 6H), 7.49- 7.42 (ms, 3H), 7.37 (t, J = 7.4 Hz, 6H), 7.33 (m, 2H), 7.28 (t, J = 7.5 Hz, 2H), 7.22 (t, J = 7.3 Hz, 1H), 5.07 (q, J = 6.4 Hz, 1H), 1.40 (d, J = 6.3 Hz, 3H). 13C{1H} NMR (126 MHz, CD3CN, 298 K): δ 146.8, 136.2, 135.4, 131.1, 129.1, 128.9, 128.0, 126.3, 72.9, 27.4. 29Si{1H} NMR (99 MHz, CD3CN, 298 K): δ -13.92 (s). IR (ATR, neat) v: 3066-2864 (w), 1589 (w), 1427 (s), 1115 (s), 694 (s). Isopropoxytriphenylsilane (4rl) Synthesis details: GP-A, acetone (2r), HSiPh3 (3l), reaction time of 24 h. Purification details: Column chromatography: silica, Et2O/hexanes (5:95) to give the product as a white solid (0.314 g, 0.986 mmol, 99% yield). NMR spectra match values previously reported.284 1H NMR (500 MHz, CD3CN, 298 K): δ 7.62 (d, J = 7.3 Hz 6H), 7.45 (t, J = 7.1 Hz, 3H), 7.41 (t, J = 7.2 Hz, 6H), 4.18 (sept, J = 6.0 Hz, 1H), 1.16 (d, J = 6.0 Hz, 6H). 13C{1H} NMR (126 MHz, CD3CN, 298 K): δ 136.2, 135.9, 131.1, 128.9, 67.3, 25.9. 29Si{1H} NMR (99 MHz, CD3CN, 298 K): δ -15.96 (s). (1-Phenylethyl)di(4-methoxyphenyl)silane (4ab) Synthesis details: GP-A, styrene (2a), H2Si(4-OCH3-C6H4)2 (3b) Selectivity before purification: 1:>99 (l/b) measured by GC. Purification details: Column chromatography: silica, Et2O/cyclohexanes (gradient 0:100 to 5:95) to give the product as a clear oil (0.179 g, 0.514 mmol, 51% yield, l/b = 1:>99). 124 1H NMR (500 MHz, CD3CN, 298 K): δ 7.48 (d, J = 8.6 Hz, 2H), 7.31 (d, J = 8.6 Hz, 2H), 7.17 (t, J = 7.6 Hz, 2H), 7.08-7.06 (ms, 3H), 6.95 (d, J = 8.6 Hz, 2H), 6.85 (d, J = 8.6 Hz, 2H), 4.76 (d, J = 3.9 Hz, 1JH– Si = 193.8 Hz, 1H), 3.79 (s, 3H), 3.74 (s, 3H), 2.85 (qd, J = 7.5, 3.9 Hz, 1H), 1.40 (d, J = 7.5 Hz, 3H). 13C{1H} NMR (126 MHz, CD3CN, 298 K): δ 162.1, 162.0, 146.0, 137.9, 137.8, 129.1, 128.6, 125.8, 125.2, 125.1, 114.8, 114.6, 55.7, 55.7, 27.7, 17.2. 29Si{1H} NMR (99 MHz, CD3CN, 298 K): δ -8.35 (s). IR (ATR, neat) v: 3058-2834 (w), 2107 (s, Si–H), 1591 (s), 1028 (s), 798 (s). ASAP/HRMS (m/z): [M+] calculated for C22H24O2Si 348.1546, found 348.1534. (1-Phenylethyl)di(4-methylphenyl)silane (4ac) Synthesis details: GP-A, styrene (2a), H2Si(4-Me-C6H4)2 (3c) Selectivity before purification: 1:>99 (l/b) measured by GC. Purification details: Column chromatography: silica, benzene/hexanes (gradient 0:100 to 5:95) to give the product as a clear oil (0.314 mg, 0.992 mmol, 99% yield, l/b = 1:>99). 1H NMR (500 MHz, CD3CN, 298 K): δ 7.46 (d, J = 7.6 Hz, 2H), 7.29 (d, J = 7.4 Hz, 2H), 7.21 (d, J = 7.4 Hz, 2H), 7.17 (t, J = 7.5 Hz, 2H), 7.12-7.05 (ms, 5H), 4.76 (d, J = 4.0 Hz, 1JH–Si = 194.3 Hz, 1H), 2.89 (qd, J = 7.5, 4.0 Hz, 1H), 2.34 (s, 3H), 2.28 (s, 3H), 1.41 (d, J = 7.5 Hz, 3H). 13C{1H} NMR (126 MHz, CD3CN, 298 K): δ 145.9, 140.9, 140.7, 136.4, 136.3, 130.8, 130.7, 129.8, 129.6, 129.1, 128.7, 125.8, 27.4, 21.6, 21.5, 17.3. 29Si{1H} NMR (99 MHz, CD3CN, 298 K): δ -7.76 (s). 125 IR (ATR, neat) ν: 3059-2866 (s), 2110 (s, Si–H), 1599 (s), 1109 (s), 777 (s). ASAP/HRMS (m/z): [M+] calculated for C22H24Si 316.1647, found 316.1645. (1-Phenylethyl)di(3-fluorophenyl)silane (4ad) Synthesis details: GP-A, styrene (2a), H2Si(3-F-C6H4)2 (3d). Selectivity before purification: 1:>99 (l/b) measured by GC. Purification details: Column chromatography: silica, benzene/hexanes (gradient 0:100 to 5:95) to give the product as a clear oil (0.249 g, 0.767 mmol, 77% yield, l/b = 1:>99). 1H NMR (500 MHz, CD3CN, 298 K): δ 7.47-7.40 (ms, 2H) 7.34-7.29 (ms, 2H), 7.21-7.18 (ms, 4H), 7.12-7.06 (ms, 5H), 4.80 (d, J = 4.4 Hz, 1JH–Si = 200.6 Hz, 1H), 2.96 (qd, J = 7.5, 4.4 Hz, 1H), 1.43 (t, J = 7.5 Hz, 3H). 13C{1H} NMR (126 MHz, CD3CN, 298 K): δ 164.5 (d, J = 246.8 Hz), 162.5 (d, J = 246.5 Hz), 145.0, 136.9 (d, J = 4.3 Hz), 136.8 (d, J = 4.4 Hz), 132.3 (d, J = 3.0 Hz), 132.2 (d, J = 2.8 Hz), 131.4 (d, J = 7.0 Hz), 131.1 (d, J = 7.2 Hz), 129.3, 128.7, 126.2, 122.4 (d, J = 19.5 Hz), 122.3 (d, J = 19.1 Hz), 118.0 (d, J = 21.8 Hz), 117.8 (d, J = 21.1 Hz), 26.9, 17.0. 19F NMR (471 MHz, CD3CN, 298 K): δ -117.68 (td, J = 8.8, 7.0 Hz, 1F), -117.96 (td, J = 8.5, 6.4 Hz, 1F). 29Si{1H} NMR (99 MHz, CD3CN, 298 K): δ -8.00 (s). IR (ATR, neat) v: 3061-2870 (w), 2125 (s, Si–H), 1574 (s), 1215 (s), 775 (s). ASAP/HRMS (m/z): [M+] calculated for C20H18F2Si 324.1146, found 324.1171. (1-Phenylethyl)di[4-(trifluoromethyl)phenyl]silane (4ae) 126 Synthesis details: GP-A, styrene (2a), H2Si(4-CF3-C6H4)2 (3e). Selectivity before purification: 1:>99 (l/b) measured by GC. Purification details: Column chromatography: silica, benzene/hexanes (5:95) to give the product as a clear oil (0.266 g, 0.627 mmol, 63% yield, l/b = 1:>99). 1H NMR (500 MHz, C6D6, 298 K): δ 7.37 (d, J = 7.7 Hz, 2H), 7.28 (d, J = 7.8 Hz, 2H), 7.26 (d, J = 7.7 Hz, 2H), 7.12 (d, J = 7.7 Hz, 2H), 7.06 (t, J = 7.5 Hz, 2H), 6.98 (t, J = 7.4 Hz, 1H), 6.86 (d, J = 7.6 Hz, 2H), 4.83 (d, J = 3.6 Hz, 1JH–Si = 201.7 Hz, 1H), 2.54 (qd, J = 7.5, 3.6 Hz, 1H), 1.27 (d, J = 7.5 Hz, 3H). 13C{1H} NMR (126 MHz, C6D6, 298 K): δ 143.3, 137.5, 137.4, 136.2, 136.1, 132.2 (q, J = 32.2 Hz), 132.1 (q, J = 32.2 Hz), 128.8, 127.9, 125.9, 124.9 (q, J = 3.7 Hz), 124.7 (q, J = 3.8 Hz), 124.80 (q, J = 272.4 Hz)*, 124.78 (q, J = 272.4 Hz)**, 26.5, 16.4. *Note that the two most downfield peaks of this quartet (assigned to a CF3) are obscured by the C6D6 peak at 128.1 ppm and the product peak at 125.9 ppm. **Note that the most downfield peak of this quartet (assigned to a CF3) is obscured by the C6D6 peak at 128.1 ppm. 19F NMR (471 MHz, C6D6, 298 K): δ -62.81 (s, 3F), -62.87 (s, 3F). 29Si{1H} NMR (99 MHz, C6D6, 298 K): δ -9.10 (s). IR (ATR, neat) v: 3035-2881 (w), 2125 (m, Si–H), 1317 (s), 1057 (s), 800 (s). ASAP/HRMS (m/z): [M+] calculated for C22H18F6Si 424.1082, found 424.1079. (1-Phenylethyl)di(3-methylphenyl)silane (4af) Synthesis details: GP-A, styrene (2a), H2Si(3-Me-C6H4)2 (3f). Selectivity before purification: 1:>99 (l/b) measured by GC. 127 Purification details: Column chromatography: silica, benzene/hexanes (5:95) to give the product as a clear oil (0.248 mg, 0.784 mmol, 78% yield, l/b = 1:>99). 1H NMR (500 MHz, CD3CN, 298 K): δ 7.41-7.37 (ms, 2H), 7.30- 7.25 (ms, 2H), 7.22-7.17 (ms, 6H), 7.10-7.06 (ms, 3H), 4.76 (d, J = 4.1 Hz, 1JH–Si = 195.0 Hz, 1H), 2.92 (qd, J = 7.4, 4.2 Hz, 1H), 2.32 (s, 3H), 2.24 (s, 3H), 1.42 (d, J = 7.4 Hz, 3H). 13C{1H} NMR (126 MHz, CD3CN, 298 K): δ 145.8, 138.6, 138.3, 136.9, 136.9, 134.4, 134.2, 133.3, 133.2, 131.5, 131.3, 129.1, 129.0, 128.8, 128.7, 125.9, 27.3, 21.5, 21.4, 17.3. 29Si{1H} NMR (99 MHz, CD3CN, 298 K): δ -7.25 (s). IR (ATR, neat) ν: 3059-2866 (w), 2112 (s, Si–H), 1448 (s), 1117 (s), 694 (s). ASAP/HRMS (m/z): [M+] calculated for C22H24Si 316.1647, found 316.1630. (1-Phenylethyl)di(2-methylphenyl)silane (4ag) Synthesis details: GP-A, styrene (2a), H2Si(2-Me-C6H4)2 (3g). Selectivity before purification: 1:>99 (l/b) measured by GC. Purification details: Column chromatography: silica, cyclohexane to give the product as a clear oil (0.294 g, 0.929 mmol, 93% yield, l/b = 1:>99). 1H NMR (500 MHz, CD3CN, 298 K): δ 7.66 (d, J = 7.3 Hz, 1H), 7.48 (d, J = 7.4 Hz, 1H), 7.34 (t, J = 7.5 Hz, 1H), 7.25-7.14 (ms, 7H), 7.09- 7.03 (ms, 3H), 5.05 (d, J = 5.3 Hz, 1JH–Si = 195.1 Hz, 1H), 3.09 (qd, J = 7.5, 5.3 Hz, 1H), 2.25 (s, 3H), 2.06 (s, 3H), 1.46 (d, J = 7.5 Hz, 3H). 128 13C{1H} NMR (126 MHz, CD3CN, 298 K): δ 146.1, 145.3, 145.2, 136.9, 136.9, 133.7, 133.5, 131.0, 130.83, 130.79, 130.5, 129.2, 128.7, 126.1, 125.9, 125.8, 26.2, 22.9, 22.7, 17.9. 29Si{1H} NMR (99 MHz, CD3CN, 298 K): δ -14.98 (s). IR (ATR, neat) v: 3055-2868 (w), 2127 (m, Si–H), 1448 (m), 1126 (m), 742 (s). ASAP/HRMS (m/z): [M+] calculated for C22H24Si 316.1647, found 316.1650. (1-Phenylethyl)phenylmesitylsilane (4ah) Synthesis details: GP-A, styrene (2a), H2SiMesPh (3h). Selectivity before purification: 1:>99 (l/b) measured by GC. Purification details: Column chromatography: silica, benzene/hexanes (gradient 0:100 to 5:95) to give the product as a viscous, clear oil (0.317 g, 0.959 mmol, 96% yield, l/b = 1:>99). The major products isolated are two diastereomers denoted diastereomer A and diastereomer B. The ratio of these isomers determined by integration of the Si–H was found to be 1.1:1 (AlB) (Figure S262, S272). A second, slow, gradient column with benzene/hexanes (0:100-5:95) as the eluent was carried out, with careful analysis of the fractions to obtain better separation of the two diastereomers for easier characterization. The first set of fractions contained primarily diastereomer A (A:B = 7.1:1, Figures S263-266), and the second set of fractions contained primarily diastereomer B (A:B = 1:3.8, Figures S267-S271). Using these two sets of NMR spectra, we were able to assign all peaks to either diastereomer A or B. Diastereomer A: 129 1H NMR (500 MHz, CDCl3, 298 K): δ 7.28 (m, 3H, overlapping with CHCl3 peak), 7.23 (d, J = 7.6 Hz, 2H), 7.17-7.13 (ms, 3H), 7.10 (d, J = 7.2 Hz, 2H), 6.88 (s, 2H), 5.13 (d, J = 5.8 Hz, 1JH–Si = 196.0 Hz, 1H), 2.94 (m, 1H), 2.38 (s, 6H), 2.30 (s, 3H), 1.43 (d, J = 7.5 Hz, 3H). 29Si{1H} NMR (119 MHz, CDCl3, 298 K): δ -17.92 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 145.7, 145.3, 139.8, 135.4, 134.2, 129.2, 128.9, 128.5, 128.2, 127.7, 125.3, 27.7, 24.7, 21.3, 17.8. Diastereomer B: 1H NMR (500 MHz, CDCl3, 298 K): δ 7.60 (d, J = 7.3 Hz, 2H), 7.35- 7.30 (ms, 3H), 7.09 (d, J = 7.2 Hz, 2H), 7.04 (d, J = 7.5 Hz, 2H), 7.00 (t, J = 7.1 Hz, 1H), 6.67 (s, 2H), 5.11 (d, J = 5.39 Hz, 1JH–Si = 195.8 Hz, 1H), 3.00 (app pentet, J = 6.9 Hz, 1H), 2.18 (s, 3H), 2.16 (s, 6H), 1.65 (d, J = 7.5 Hz, 3H). 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 145.3, 144.9, 139.4, 135.5, 135.2, 129.2, 128.5, 128.2, 128.0, 127.8, 127.4, 124.9, 26.5, 24.5, 21.2, 18.3. 29Si{1H} NMR (119 MHz, CDCl3, 298 K): δ -17.45 Mixture of diastereomers A and B (A/B = 1.1:1): IR (ATR, neat) ν: 3030-2867 (w), 2140 (m, Si–H), 1603 (m), 1103 (w), 695 (s). ASAP/HRMS (m/z): [M+] calculated for C23H26Si 330.1804, found 330.1850. (1-Phenylethyl)(1-naphthyl)phenylsilane (4ai) Synthesis details: GP-A, styrene (2a), H2SiPh(1-naphthyl) (3i). Selectivity before purification: 1:>99 (l/b) measured by GC. Purification details: Column chromatography: silica, benzene/hexanes (5:95) to give the product as a viscous, clear oil (0.320 g, 0.945 mmol, 95% yield, l/b = 1:>99). 130 The major products isolated are two diastereomers denoted diastereomer A and diastereomer B. The ratio of these isomers determined by integration of the Si–H was found to be 1:1.04 (AlB, Figures S273, S284). A slow, gradient column with benzene/hexanes (0:100-5:95) as the eluent was carried out, with careful analysis of the fractions to obtain better separation of the two diastereomers for easier characterization. The first set of fractions contained primarily diastereomer A (A:B = 8.3:1, Figures S274-278), and the second set of fractions contained primarily diastereomer B (A:B = 1:4.5, Figures S279-S283). Using these two sets of NMR spectra, we were able to assign all peaks to either diastereomer A or B. Diastereomer A: 1H NMR (500 MHz, CDCl3, 298 K): δ 8.02 (d, J = 8.4 Hz, 1H), 7.93 (d, J = 8.1 Hz, 1H), 7.87 (d, J = 8.0 Hz, 1H), 7.80 (dd, J = 6.7 Hz, 1.0 Hz, 1H), 7.47 (dd, J = 8.0, 6.8 Hz, 2H), 7.41 (m, 1H), 7.29 (t, J = 7.4 Hz, 1H), 7.24 (d, J = 6.4 Hz, 2H), 7.20-7.17 (ms, 4H), 7.12 (d, J = 7.4 Hz, 1H), 7.08 (m, 2H), 5.25 (d, J = 4.4 Hz, 1JH–Si = 197.5 Hz, 1H), 3.04 (qd, J = 7.6 Hz, 4.4 Hz 1H), 1.46 (d, J = 7.6 Hz, 3H). 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 144.7, 137.5, 136.3, 135.7, 133.5, 133.3, 131.7, 130.7, 129.6, 129.0, 128.4, 128.3, 128.0, 127.8, 126.2, 125.8, 125.3, 125.2, 27.2, 17.3. 29Si{1H} NMR (99 MHz, CDCl3, 298 K): δ -10.41 (s). Diastereomer B: 1H NMR (500 MHz, CDCl3, 298 K): δ 7.88 (d, J = 8.5 Hz, 1H), 7.85 (d, J = 8.3 Hz, 1H) 7.80 (d, J = 8.0 Hz, 1H), 7.70 (d, J = 6.9 Hz, 1H), 7.60 (d, J = 7.2 Hz, 2H), 7.42-7.37 (ms, 3H), 7.36-7.30 (ms, 3H), 7.08 (m, 2H), 7.03-6.98 (ms, 3H), 5.28 (d, J = 3.7 Hz, 1JH–Si = 197.2 Hz, 1H), 3.06 (qd, J = 7.5 Hz, 3.7 Hz, 1H), 1.55 (d, J = 7.5 Hz, 3H). 131 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 144.9, 137.4, 136.0, 135.9, 133.7, 133.3, 131.6, 130.6, 129.8, 128.8, 128.3, 128.2, 128.1, 127.7, 125.9, 125.6, 125.1, 125.0, 26.9, 17.2. 29Si{1H} NMR (99 MHz, CDCl3, 298 K): δ -9.94 (s). Mixture of diastereomers A and B (A/B = 1.04:1): IR (ATR, neat) ν: 3053-2867 (w), 2116 (m, Si –H), 1427 (m), 1033 (m), 695 (s). ASAP/HRMS (m/z): [M+] calculated for C24H22Si 338.1491, found 338.1478. (1-Phenylethyl)diethylsilane (4aj) Synthesis details: GP-A, styrene (2a), H2SiEt2 (3j). Selectivity before purification: 1:20 (l/b) measured by GC. Purification details: Column chromatography: silica, benzene/hexanes (5:95) to give the product as a clear oil (0.180 g, 0.936 mmol, 94% yield, l/b = 1:14). NMR spectra match values previously reported.48,93 The major product isolated is the branched isomer, and the linear isomer is seen in the NMR spectra as well. The ratio of these isomers was determined by relative integrations of the benzylic C–H positions and was found to be 1:14 (l/b). The branched product is fully characterized below, and the peaks visible and clearly assignable to the linear isomer are given directly following the NMR characterization of the branched product. IR (ATR, neat) ν: 3070-2875 (m), 2094 (m, Si–H), 1452 (m), 1014 (m), 800 (s). Branched product: 1H NMR (500 MHz, CD3CN, 298 K): δ 7.25 (t, J = 7.6 Hz, 2H), 7.14 (d, J = 7.6 Hz, 2H), 7.10 (t, J = 7.5 Hz, 1H), 3.63 (m, 1JH–Si = 180.5 132 Hz, 1H), 2.41 (qd, J = 7.5, 3.2 Hz, 1H), 1.41 (d, J = 7.5 Hz, 3H), 0.96 (t, J = 7.9 Hz, 3H), 0.89 (t, J = 8.0 Hz, 3H), 0.63 (dq, J = 7.9, 3.0 Hz, 2H), 0.52 (m, 2H). 13C{1H} NMR (126 MHz, CD3CN, 298 K): δ 147.0, 129.2, 128.0, 125.5, 26.5, 16.4, 8.55, 8.51, 2.3, 2.2. 29Si{1H} NMR (99 MHz, CD3CN, 298 K): δ 5.32 (s). Linear product: 1H NMR (500 MHz, CD3CN, 298 K): δ 3.69 (s, 0.08H), 2.69 (m, 0.15H), 1.00 (m). 13C{1H} NMR (126 MHz, CD3CN, 298 K): 146.0, 129.3, 128.8, 126.5, 31.4, 13.6, 3.3. (1-Phenylethyl)tri(4-methoxyphenyl)silane (4ak) Synthesis details: GP-D, styrene (2a, 3 equiv), HSi(4-OCH3-C6H4)3 (3k, 1 equiv). Selectivity before purification: 1:>99 (l/b) measured by GC. Purification details: Column chromatography: silica, Et2O/hexanes (gradient 0:100 to 5:95) to give the product as a white solid (0.427 g, 0.939 mmol, 94% yield, l/b = 1:>99). 1H NMR (500 MHz, CD3CN, 298 K): δ 7.30 (d, J = 8.6 Hz, 6H), 7.12- 7.05 (ms, 3H), 6.91-6.87 (ms, 8H), 3.78 (s, 9H), 3.11 (q, J = 7.5 Hz, 1H), 1.45 (d, J = 7.5 Hz, 3H). 13C{1H} NMR (126 MHz, CD3CN, 298 K): δ 161.8, 146.1, 138.6, 129.5, 128.8, 126.1, 125.8, 114.5, 55.7, 28.6, 18.3. 29Si{1H} NMR (99 MHz, CD3CN, 298 K): δ -11.60 (s). IR (ATR, neat) v: 3028-2837 (w), 1509 (s), 1178 (s), 1028 (s), 797 (s). ASAP/HRMS (m/z): [M+] calculated for C29H30O3Si 454.1964, found 454.1984. 133 (1-Phenylethyl)triphenylsilane (4al) Synthesis details: GP-D, styrene (2a, 3.3 mmol, 3.0 equiv), HSiPh3 (3l, 1.1 mmol, 1.0 equiv). Selectivity before purification: 1:>99 (l/b) measured by GC. Purification details: Column chromatography: silica, benzene/hexanes (5:95) to give the product as a white solid (0.374 g, 1.03 mmol, 93% yield, l/b = 1:>99). 1H NMR (500 MHz, CDCl3, 298 K): δ 7.44-7.42 (ms, 9H), 7.36-7.33 (ms, 6H), 7.17-7.11 (ms, 3H), 6.91 (dd, J = 7.8, 1.8 Hz, 2H), 3.12 (q, J = 7.6 Hz, 1H), 1.60 (d, J = 7.6 Hz, 3H). 13C{1H} NMR (151 MHz, CDCl3, 298 K): δ 144.5, 136.6, 133.9, 129.6, 128.8, 128.1, 127.8, 125.2, 28.2, 17.9. 29Si{1H} NMR (119 MHz, CDCl3, 298 K): δ -11.08 (s). IR (ATR, neat) v: 3064-2860 (w), 1423 (m), 1107 (m), 997 (w), 696 (s). ASAP/HRMS (m/z): [M+] calculated for C26H24Si 364.1647, found 364.1649. Using GP-A: 0.269 g, 0.738 mmol, 74% yield, l/b = 1:>99 (1-Phenylethyl)tri[4-(trifluoromethyl)phenyl]silane (4am) Synthesis details: GP-D, styrene (2a, 1 equiv), HSi(4-CF3-C6H4)3 (3m, 1.1 equiv). Selectivity before purification: 1:>99 (l/b) measured by GC. P urification details: Column chromatography: silica, benzene/hexanes (5:95) to give the product as a white solid (0.537 g, 0.944 mmol, 94% yield, l/b = 1:>99). 134 1H NMR (500 MHz, CDCl3, 298 K): δ 7.60 (d, J = 7.7 Hz, 6H), 7.45 (d, J = 7.7 Hz, 6H), 7.16-7.15 (ms, 3H), 6.84 (m, 2H), 3.14 (q, J = 7.5 Hz, 1H), 1.58 (d, J = 7.5 Hz, 3H). 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 142.8, 137.4, 136.7, 132.2 (q, J = 32.5 Hz), 128.6, 126.0, 124.2 (q, J = 272.5 Hz), 124.7 (q, J = 3.7 Hz), 27.7, 17.6. 19F NMR (471 MHz, CDCl3, 298 K): δ -63.10 (s). 29Si{1H} NMR (99 MHz, CDCl3, 298 K): δ -11.09 (s). IR (ATR, neat) v: 3026-2845 (w), 1392 (m), 1319 (s), 1057 (s), 700 (s). ASAP/HRMS (m/z): [M+] calculated for C29H21F9Si 568.1269, found 568.1272. Using GP-A: 0.449 g, 0.786 mmol, 79% yield, l/b = 1:>99. (1-Phenylethyl)diphenylmethylsilane (4an) Synthesis details: GP-D, styrene (2a), HSiMePh2 (3n). Selectivity before purification: 1:>99 (l/b) measured by GC. Purification details: Column chromatography: silica, hexanes, to give the product as a white solid (0.227 g, 0.750 mmol, 75% yield, l/b = 1:>99). NMR spectra match values previously reported.285 1H NMR (500 MHz, CD3CN, 298 K): δ 7.61 (m, 2H), 7.45-7.35 (ms, 6H), 7.30 (m, 2H), 7.15 (m, 2H), 7.07 (t, J = 7.3, 1H), 7.00 (d, J = 7.4 Hz, 2H), 2.94 (q, J = 7.6 Hz, 1H), 1.42 (d, J = 7.6 Hz, 3H), 0.52 (s, 3H). 13C{1H} NMR (126 MHz, CD3CN, 298 K): δ 145.7, 136.9, 136.5, 135.9, 135.7, 130.3, 130.2, 128.81, 128.80, 128.7, 128.6, 125.6, 28.4, 16.5, -6.1. 29Si{1H} NMR (99 MHz, CD3CN, 298 K): δ -6.30 (s). 135 (1-Phenylethyl)phenyldimethylsilane (4ao) Synthesis details: GP-D, styrene (2a), HSiMe2Ph (3o). Selectivity before purification: 1:>99 (l/b) measured by GC. Purification details: Column chromatography: silica, hexanes, to give the product as a white solid (0.177 g, 0.736 mmol, 74% yield, l/b = 1:>99). NMR spectra match values previously reported.285 1H NMR (500 MHz, CD3CN, 298 K): δ 7.44 (d, J = 7.6 Hz, 2H), 7.38- 7.31 (ms, 3H), 7.18 (t, J = 7.7 Hz, 2H), 7.07 (t, J = 7.1 Hz, 1H), 6.99 (d, J = 7.5 Hz, 2H), 2.45 (q, J = 7.5 Hz, 1H), 1.32 (d, J = 7.5 Hz, 3H), 0.23 (s, 3H), 0.18 (s, 3H). 13C{1H} NMR (126 MHz, CD3CN, 298 K): δ 146.4, 138.6, 135.1, 130.0, 128.9, 128.6, 128.3, 125.4, 29.9, 15.6, -4.2, -5.2 29Si{1H} NMR (99 MHz, CD3CN, 298 K): δ -1.05 (s). (1-Phenylethyl)triethoxysilane (4ap) Synthesis details: GP-E, styrene, HSi(OEt)3 (3p, 2 equiv). Selectivity before purification: 1:>99 (l/b) measured by GC. Purification details: Column chromatography Et2O:hexanes (gradient 0:100 to 1:99) to give the product as a clear oil (0.167 g, 0.622 mmol, 62% yield, l/b = 1:>99). NMR spectra match values previously reported.286 Tetraethoxysilane, formed from silane redistribution, was inseparable from the product and is seen in the NMR spectra. Integration of the methylene protons gives a 1:12 (tetraethoxysilane:product) ratio. The branched product is fully characterized below. 1H NMR (500 MHz, CDCl3, 298 K): δ 7.29-7.25 (ms, 4H), 7.13 (m, 1H), 3.75 (q, J = 7.0 Hz, 6H), 2.35 (q, J = 7.6 Hz, 1H), 1.46 (d, J = 7.6 Hz, 3H), 1.18 (t, J = 7.0 Hz, 9H). 136 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 144.2, 128.2, 128.0, 125.0, 58.9, 26.3, 18.4, 15.7. 29Si{1H} NMR (119 MHz, CDCl3, 298 K): δ -52.45 (s). IR (ATR, neat) v: 3081-2874 (w), 1601 (w), 1389 (w), 1704 (s), 776 (s). ASAP/HRMS (m/z): [M+] calculated for C14H24O3Si 268.1495, found 268.1469. 1,1,1,3,5,5,5-Heptamethyl-3-(1-phenylethyl)trisiloxane (4aq) Synthesis details: GP-D, styrene (1.0 equiv), HSiCH3(OSiMe3)2 (3q, 2.0 equiv). Selectivity before purification: 1:>99 (l/b) measured by GC-MS. Purification details: Column chromatography hexanes to give the product as a clear oil (0.201 g, 0.615 mmol, 62% yield, l/b = 1:>99). 1H NMR (500 MHz, CDCl3, 298 K): δ 7.23 (m, 2H), 7.11-7.07 (ms, 3H), 2.10 (q, J =7.5 Hz, 1H), 1.35 (d, J = 7.5 Hz, 3H), 0.03 (s, 9H), 0.03 (s, 9H), -0.04 (s, 3H). 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 145.0, 128.1, 127.8, 124.6, 30.9, 14.7, 1.88, 1.86, -2.3. 29Si{1H} NMR (99 MHz, CDCl3, 298 K): δ 7.67 (s), 7.52 (s), -26.55 (s). IR (ATR, neat) v: 3061-2872 (m), 1492 (w), 1251 (s), 1041 (s), 834 (s). ASAP/HRMS (m/z): [M+] calculated for C15H30O2Si3 326.1554, found 326.1559. (1-Phenylethyl)trichlorosilane (4ar) Synthesis details: GP-C, styrene (2a), HSiCl3 (3r, 1.25 equiv). Selectivity before purification: 1:>99 (l/b) measured by GC. 137 Purification details: Distillation (approximately 0.05 Torr, 60 °C) to give the product as a clear oil (0.200 g, 0.835 mmol, 84% yield, l/b = 1:>99). 1H NMR (500 MHz, CDCl3, 298 K): δ 7.34 (m, 2H), 7.27-7.24 (ms, 3H), 2.90 (q, J = 7.5 Hz, 1H), 1.63 (d, J = 7.5 Hz, 3H). 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 138.1, 128.8, 128.5, 127.0, 36.3, 14.5. 29Si{1H} NMR (99 MHz, CDCl3, 298 K): δ 9.82 (s). IR (ATR, neat) v: 3062-2875 (w), 1602 (w), 1492 (m), 760 (s), 694 (s). ASAP/HRMS (m/z): [M+] calculated for C8H9Cl3Si 237.9539, found 237.9515. (1-Phenylethyl)dichloromethylsilane (4as) Synthesis details: GP-C, styrene (2a), HSiCl2Me (3s, 1.25 equiv). Selectivity before purification: 1:>99 (l/b) measured by GC. Purification details: Distillation (approximately 0.05 Torr, 60 °C) to give the product as a clear oil (0.169 g, 0.771 mmol, 77% yield, l/b = 1:>99). 1H NMR (500 MHz, CDCl3, 298 K): δ 7.31 (t, J = 7.70 Hz, 2H), 7.23- 7.19 (ms, 3H), 2.66 (q, J = 7.5 Hz, 1H), 1.56 (d, J = 7.5 Hz, 3H), 0.64 (s, 3H). 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 140.3, 128.7, 128.1, 126.3, 34.0, 14.4, 3.4. 29Si{1H} NMR (99 MHz, CDCl3, 298 K): δ 29.76 (s). IR (ATR, neat) v: 3083-2874 (w), 1600 (w), 1259 (s), 1076-995 (m), 696 (s). 138 ASAP/HRMS (m/z): [M+] calculated for C9H12Cl2Si 218.0085, found 218.0040. c. Incompatible Substrates A.1.6. NMR and IR Spectra a. Nickel Complexes 139 Figure A.1. 1H NMR spectrum of (dvtms)Ni(ITMe) (1a) recorded in C6D6 at 298 K. Figure A.2. 13C{1H} NMR spectrum of (dvtms)Ni(ITMe) (1a) recorded in C6D6 at 298 K. 140 Figure A.3. 29Si NMR spectrum of (ITMe)Ni(dvtms) (1a) recorded in in C6D6 at 298 K. Figure A.4. COSY NMR spectrum of (dvtms)Ni(ITMe) (1a) recorded in C6D6 at 298 K. 141 Figure A.5. HSQC NMR spectrum of (dvtms)Ni(ITMe) (1a) recorded in C6D6 at 298 K. Figure A.6. IR spectrum of (dvtms)Ni(ITMe) (1a) recorded as a KBr pellet at 298 K. 142 Figure A.7. 1H NMR spectrum of (dvtms)Ni(IMes) (1b) recorded in C6D6 at 298 K. Figure A.8. 13C{1H} NMR spectrum of (dvtms)Ni(IMes) (1b) recorded in C6D6 at 298 K. 143 Figure A.9. COSY NMR spectrum of (dvtms)Ni(IMes) (1b) recorded in C6D6 at 298 K. Figure A.10. HSQC NMR spectrum of (dvtms)Ni(IMes) (1b) recorded in C6D6 at 298 K. 144 Figure A.11. IR spectrum of (dvtms)Ni(IMes) (1b) recorded as a KBr pellet at 298 K. Figure A.12. 1H NMR spectrum of (diallylether)Ni(IMes) (1f) recorded in C6D6 at 298 K. 145 Figure A.13. 13C{1H} NMR spectrum of (diallylether)Ni(IMes) (1f) recorded in C6D6 at 298 K. Figure A.14. COSY NMR spectrum of (diallylether)Ni(IMes) (1f) recorded in C6D6 at 298 K. 146 Figure A.15. HSQC NMR spectrum of (diallylether)Ni(IMes) (1f) recorded in C6D6 at 298 K. Figure A.16. IR spectrum of (diallylether)Ni(IMes) (1f) recorded as a KBr pellet at 298 K. 147 b. Styrene Derivative Figure A.17. IR spectrum of 4-acetoxystyrene (2k) recorded neat at 298 K. c. Silanes Figure A.18. 1H NMR spectrum of di(4-methoxyphenyl)silane (3b) recorded in CDCl3 at 298 K. 148 Figure A.19. 13C{1H} NMR spectrum of di(4-methoxyphenyl)silane (3b) recorded in CDCl3 at 298 K. Figure A.20. 29Si NMR spectrum of di(4-methoxyphenyl)silane (3b) recorded in CDCl3 at 298 K. 149 Figure A.21. COSY NMR spectrum of di(4-methoxyphenyl)silane (3b) recorded in CDCl3 at 298 K. Figure A.22. HSQC NMR spectrum of di(4-methoxyphenyl)silane (3b) recorded in CDCl3 at 298 K. 150 Figure A.23. IR spectrum of di(4-methoxyphenyl)silane (3b) recorded neat at 298 K. Figure A.24. 1H NMR spectrum of di(3-fluorophenyl)silane (3d) recorded in C6D6 at 298 K. 151 Figure A.25. 13C{1H} NMR spectrum of di(3-fluorophenyl)silane (3d) recorded in C6D6 at 298 K. Figure A.26. 19F NMR spectrum of di(3-fluorophenyl)silane (3d) recorded in C6D6 at 298 K. 152 Figure A.27. 29Si NMR spectrum of di(3-fluorophenyl)silane (3d) recorded in C6D6 at 298 K. Figure A.28. COSY NMR spectrum of di(3-fluorophenyl)silane (3d) recorded in C6D6 at 298 K. 153 Figure A.29. HSQC NMR spectrum of di(3-fluorophenyl)silane (3d) recorded in C6D6 at 298 K. Figure A.30. IR spectrum of di(3-fluorophenyl)silane (3d) recorded neat at 298 K. 154 Figure A.31. 1H NMR spectrum of di(4-trifluoromethylphenyl)silane (3e) recorded in C6D6 at 298 K. Figure A.32. 13C{1H} NMR spectrum of di(4-trifluoromethylphenyl)silane (3e) recorded in C6D6 at 298 K. 155 Figure A.33. 19F NMR spectrum of di(4-trifluoromethylphenyl)silane (3e) recorded in C6D6 at 298 K. Figure A.34. 29Si NMR spectrum of di(4-trifluoromethylphenyl)silane (3e) recorded in C6D6 at 298 K. 156 Figure A.35. COSY NMR spectrum of di(4-trifluoromethylphenyl)silane (3e) recorded in C6D6 at 298 K. Figure A.36. HSQC NMR spectrum of di(4-trifluoromethylphenyl)silane (3e) recorded in C6D6 at 298 K. 157 Figure A.37. IR spectrum of di(4-trifluoromethylphenyl)silane (3e) recorded neat at 298 K. Figure A.37. IR spectrum of di(3-methylphenyl)silane (3f) recorded neat at 298 K. 158 Figure A.38. 1H NMR spectrum of di(2-methylphenyl)silane (3g) recorded in CDCl3 at 298 K. Figure A.39. 13C{1H} NMR spectrum of di(2-methylphenyl)silane (3g) recorded in CDCl3 at 298 K. 159 Figure A.40. 29Si NMR spectrum of di(2-methylphenyl)silane (3g) recorded in CDCl3 at 298 K. Figure A.41. COSY NMR spectrum of di(2-methylphenyl)silane (3g) recorded in CDCl3 at 298 K. 160 Figure A.42. HSQC NMR spectrum of di(2-methylphenyl)silane (3g) recorded in CDCl3 at 298 K. Figure A.43. IR spectrum of di(2-methylphenyl)silane (3g) recorded neat at 298 K. d. Hydrosilylation Products 161 Figure A.43. 1H NMR spectrum of (1-phenylethyl)diphenylsilane (4aa) recorded in CD3CN at 298 K. Figure A.44. 13C{1H} NMR spectrum of (1-phenylethyl)diphenylsilane (4aa) recorded in CD3CN at 298 K. 162 Figure A.45. 29Si{1H} NMR spectrum of (1-phenylethyl)diphenylsilane (4aa) recorded in CD3CN at 298 K. Figure A.46. 1H NMR spectrum of [1-(4-dimethylaminophenyl)ethyl]diphenylsilane (4ba) recorded in CDCl3 at 298 K. 163 Figure A.47. 13C{1H} NMR spectrum of [1-(4-dimethylaminophenyl)ethyl]diphenylsilane (4ba) recorded in CDCl3 at 298 K. Figure A.48. 29Si{1H} NMR spectrum of [1-(4-dimethylaminophenyl)ethyl]diphenylsilane (4ba) recorded in CDCl3 at 298 K. 164 Figure A.49. IR spectrum of [1-(4-dimethylaminophenyl)ethyl]diphenylsilane (4ba) recorded neat at 298 K. Figure A.50. 1H NMR spectrum of [1-(4-methoxyphenyl)ethyl]diphenylsilane (4ca) recorded in CD3CN at 298 K. 165 Figure A.51. 13C{1H} NMR spectrum of [1-(4-methoxyphenyl)ethyl]diphenylsilane (4ca) recorded in CD3CN at 298 K. Figure A.52. 29Si{1H} NMR spectrum of [1-(4-methoxyphenyl)ethyl]diphenylsilane (4ca) recorded in CD3CN at 298 K. 166 Figure A.53. 1H NMR spectrum of [1-(4-tert-butylphenyl)ethyl]diphenylsilane (4da) recorded in CD3CN at 298 K. Figure A.54. 13C{1H} NMR spectrum of [1-(4-tert-butylphenyl)ethyl]diphenylsilane (4da) recorded in CD3CN at 298 K. 167 Figure A.55. 29Si{1H} NMR spectrum of [1-(4-tert-butylphenyl)ethyl]diphenylsilane (4da) recorded in CD3CN at 298 K. Figure A.56. 1H NMR spectrum of [1-(4-methylphenyl)ethyl]diphenylsilane (4ea) recorded in CD3CN at 298 K. 168 Figure A.57. 13C{1H} NMR spectrum of [1-(4-methylphenyl)ethyl]diphenylsilane (4ea) recorded in CD3CN at 298 K. Figure A.58. 29Si{1H} NMR spectrum of [1-(4-methylphenyl)ethyl]diphenylsilane (4ea) recorded in CD3CN at 298 K. 169 Figure A.59. 1H NMR spectrum of [1-(4-fluorophenyl)ethyl]diphenylsilane (4fa) recorded in CD3CN at 298 K. Figure A.60. 13C{1H} NMR spectrum of [1-(4-fluorophenyl)ethyl]diphenylsilane (4fa) recorded in CD3CN at 298 K. 170 Figure A.61. 19F NMR spectrum of [1-(4-fluorophenyl)ethyl]diphenylsilane (4fa) recorded in CD3CN at 298 K. Figure A.62. 29Si{1H} NMR spectrum of [1-(4-fluorophenyl)ethyl]diphenylsilane (4fa) recorded in CD3CN at 298 K. 171 Figure A.63. 1H NMR spectrum of [1-(4-(trifluoromethyl)phenyl)ethyl]diphenylsilane (4ga) recorded in CD3CN at 298 K. Figure A.64. 13C{1H} NMR spectrum of [1-(4-(trifluoromethyl)phenyl)ethyl]diphenylsilane (4ga) recorded in CD3CN at 298 K. 172 Figure A.65. 19F NMR spectrum of [1-(4-(trifluoromethyl)phenyl)ethyl]diphenylsilane (4ga) recorded in CD3CN at 298 K. Figure A.66. 29Si{1H} NMR spectrum of [1-(4-(trifluoromethyl)phenyl)ethyl]diphenylsilane (4ga) recorded in CD3CN at 298 K. 173 Figure A.67. IR spectrum of [1-(4-(trifluoromethyl)phenyl)ethyl]diphenylsilane (4ga) recorded neat at 298 K. Figure A.68. 1H NMR spectrum of [1-(2-methylphenyl)ethyl]diphenylsilane (4ha) recorded in CDCl3 at 298 K. 174 Figure A.69. 13C{1H} NMR spectrum of [1-(2-methylphenyl)ethyl]diphenylsilane (4ha) recorded in CDCl3 at 298 K. Figure A.70. 29Si{1H} NMR spectrum [1-(2-methylphenyl)ethyl]diphenylsilane (4ha) recorded in CDCl3 at 298 K. 175 Figure A.71. IR spectrum of [1-(2-methylphenyl)ethyl]diphenylsilane (4ha) recorded neat at 298 K. Figure A.72. 1H NMR spectrum of [1-(2-naphthyl)ethyl]diphenylsilane (4ia) recorded in CD3CN at 298 K. 176 Figure A.73. 13C{1H} NMR spectrum of [1-(2-naphthyl)ethyl]diphenylsilane (4ia) recorded in CD3CN at 298 K. Figure A.74. 29Si{1H} NMR spectrum of [1-(2-naphthyl)ethyl]diphenylsilane (4ia) recorded in CD3CN at 298 K. 177 Figure A.75. 1H NMR spectrum of [1-phenylpropyl]diphenylsilane (4ja) recorded in CD3CN at 298 K. Figure A.76. 13C{1H} NMR spectrum of [1-phenylpropyl]diphenylsilane (4ja) recorded in CD3CN at 298 K. 178 Figure A.77. 29Si{1H} NMR spectrum of [1-phenylpropyl]diphenylsilane (4ja) recorded in CD3CN at 298 K. Figure A.78. 1H NMR spectrum of [1-(4-acetoxyphenyl)ethyl]diphenylsilane (4ka) recorded in CD3CN at 298 K. 179 Figure A.79. 13C{1H} NMR spectrum of [1-(4-acetoxyphenyl)ethyl]diphenylsilane (4ka) recorded in CD3CN at 298 K. Figure A.80. 29Si{1H} NMR spectrum [1-(4-acetoxyphenyl)ethyl]diphenylsilane (4ka) recorded in CD3CN at 298 K. 180 Figure A.81. 1H NMR spectrum of [1-(2-thiophenyl)ethyl]diphenylsilane (4la) recorded in CDCl3 at 298 K. Figure A.82. 13C{1H} NMR spectrum of [1-(2-thiophenyl)ethyl]diphenylsilane (4la) recorded in CDCl3 at 298 K. 181 Figure A.83. 29Si{1H} NMR spectrum [1-(2-thiophenyl)ethyl]diphenylsilane (4la) recorded in CDCl3 recorded in CD3CN at 298 K. Figure A.84. IR spectrum of [1-(2-thiophenyl)ethyl]diphenylsilane (4la) recorded neat at 298 K. 182 Figure A.85. 1H NMR spectrum of (3,3-dimethyl-1-butyl)diphenylsilane (4ma) recorded in CD3CN at 298 K. Figure A.86. 13C{1H} NMR spectrum of (3,3-dimethyl-1-butyl)diphenylsilane (4ma) recorded in CD3CN at 298 K. 183 Figure A.87. 29Si{1H} NMR spectrum (3,3-dimethyl-1-butyl)diphenylsilane (4ma) recorded in CD3CN at 298 K. Figure A.88. IR spectrum of (3,3-dimethyl-1-butyl)diphenylsilane (4ma) recorded neat at 298 K. 184 Figure A.89. 1H NMR spectrum of (2-cyclohexylethyl)diphenylsilane (4na) recorded in CD3CN at 298 K. Figure A.90. 13C{1H} NMR spectrum of (2-cyclohexylethyl)diphenylsilane (4na) recorded in CD3CN at 298 K. 185 Figure A.91. 29Si{1H} NMR spectrum (2-cyclohexylethyl)diphenylsilane (4na) recorded in CD3CN at 298 K. Figure A.92. IR spectrum of (2-cyclohexylethyl)diphenylsilane (4na) recorded neat at 298 K. 186 Figure A.92. 1H NMR spectrum of (1-decyl)diphenylsilane (4oa) recorded in CDCl3 at 298 K. Figure A.93. 13C{1H} NMR spectrum of (1-decyl)diphenylsilane (4oa) recorded in CDCl3 at 298 K. 187 Figure A.94. 29Si{1H} NMR spectrum (1-decyl)diphenylsilane (4oa) recorded in CDCl3 at 298 K. Figure A.95. IR spectrum of (1-decyl)diphenylsilane (4oa) recorded neat at 298 K. 188 Figure A.96. 1H NMR spectrum of benzyloxytriphenylsilane (4pl) recorded in CDCl3 at 298 K. Figure A.97. 13C{1H} NMR spectrum of benzyloxytriphenylsilane (4pl) recorded in CD3CN at 298 K. 189 Figure A.98. 29Si{1H} NMR spectrum benzyloxytriphenylsilane (4pl) recorded in CD3CN at 298 K. Figure A.99. IR spectrum of benzyloxytriphenylsilane (4pl) recorded neat at 298 K. 190 Figure A.100. 1H NMR spectrum of (1-phenylethoxy)triphenylsilane (4ql) recorded in CD3CN at 298 K. Figure A.101. 13C{1H} NMR spectrum of (1-phenylethoxy)triphenylsilane (4ql) recorded in CD3CN at 298 K. 191 Figure A.102. 29Si{1H} NMR spectrum (1-phenylethoxy)triphenylsilane (4ql) recorded in CD3CN at 298 K. Figure A.103. IR spectrum of (1-phenylethoxy)triphenylsilane (4ql) recorded neat at 298 K. 192 Figure A.104. 1H NMR spectrum of isopropoxytriphenylsilane (4rl) recorded in CD3CN at 298 K. Figure A.105. 13C{1H} NMR spectrum of isopropoxytriphenylsilane (4rl) recorded in CD3CN at 298 K. 193 Figure A.106. 29Si{1H} NMR spectrum isopropoxytriphenylsilane (4rl) recorded in CD3CN at 298 K. Figure A.107. 1H NMR spectrum of (1-phenylethyl)di(4-methoxyphenyl)silane (4ab) recorded in CD3CN at 298 K. 194 Figure A.108. 13C{1H} NMR spectrum of (1-phenylethyl)di(4-methoxyphenyl)silane (4ab) recorded in CD3CN at 298 K. Figure A.109. 29Si{1H} NMR spectrum (1-phenylethyl)di(4-methoxyphenyl)silane (4ab) recorded in CD3CN at 298 K. 195 Figure A.110. COSY NMR spectrum of (1-phenylethyl)di(4-methoxyphenyl)silane (4ab) recorded in CD3CN at 298 K. Figure A.111. HSQC NMR spectrum of (1-phenylethyl)di(4-methoxyphenyl)silane (4ab) recorded in CD3CN at 298 K. 196 Figure A.112. IR spectrum of (1-phenylethyl)di(4-methoxyphenyl)silane (4ab) recorded neat at 298 K. Figure A.113. 1H NMR spectrum of (1-phenylethyl)di(4-methylphenyl)silane (4ac) recorded in CD3CN at 298 K. 197 Figure A.114. 13C{1H} NMR spectrum of (1-phenylethyl)di(4-methylphenyl)silane (4ac) recorded in CD3CN at 298 K. Figure A.115. 29Si{1H} NMR spectrum (1-phenylethyl)di(4-methylphenyl)silane (4ac) recorded in CD3CN at 298 K. 198 Figure A.116. COSY NMR spectrum of (1-phenylethyl)di(4-methylphenyl)silane (4ac) recorded in CD3CN at 298 K. Figure A.117. HSQC NMR spectrum of (1-phenylethyl)di(4-methylphenyl)silane (4ac) recorded in CD3CN at 298 K. 199 Figure A.118. IR spectrum of (1-phenylethyl)di(4-methylphenyl)silane (4ac) recorded neat at 298 K. Figure A.119. 1H NMR spectrum of (1-phenylethyl)di(3-fluorophenyl)silane (4ad) recorded in CD3CN at 298 K. 200 Figure A.120. 13C{1H} NMR spectrum of (1-phenylethyl)di(3-fluorophenyl)silane (4ad) recorded in CD3CN at 298 K. Figure A.121. 19F NMR spectrum of (1-phenylethyl)di(3-fluorophenyl)silane (4ad) recorded in CD3CN at 298 K. 201 Figure A.122. 29Si{1H} NMR spectrum of (1-phenylethyl)di(3-fluorophenyl)silane (4ad) recorded in CD3CN at 298 K. Figure A.123. COSY NMR spectrum of (1-phenylethyl)di(3-fluorophenyl)silane (4ad) recorded in CD3CN at 298 K. 202 Figure A.124. HSQC NMR spectrum of (1-phenylethyl)di(3-fluorophenyl)silane (4ad) recorded in CD3CN at 298 K. Figure A.125. IR spectrum of (1-phenylethyl)di(3-fluorophenyl)silane (4ad) recorded neat at 298 K. 203 Figure A.126. 1H NMR spectrum of (1-phenylethyl)di[4-(trifluoromethyl)phenyl]silane (4ae) recorded in CD3CN at 298 K. Figure A.127. 13C{1H} NMR spectrum of (1-phenylethyl)di[4-(trifluoromethyl)phenyl]silane (4ae) recorded in CD3CN at 298 K. 204 Figure A.128. 19F NMR spectrum of (1-phenylethyl)di[4-(trifluoromethyl)phenyl]silane (4ae) recorded in CD3CN at 298 K. Figure A.129. 29Si{1H} NMR spectrum of (1-phenylethyl)di[4-(trifluoromethyl)phenyl]silane (4ae) recorded in CD3CN at 298 K. 205 Figure A.130. COSY NMR spectrum of (1-phenylethyl)di[4-(trifluoromethyl)phenyl]silane (4ae) recorded in CD3CN at 298 K. Figure A.131. HSQC NMR spectrum of (1-phenylethyl)di[4-(trifluoromethyl)phenyl]silane (4ae) recorded in CD3CN at 298 K. 206 Figure A.132. IR spectrum of (1-phenylethyl)di[4-(trifluoromethyl)phenyl]silane (4ae) recorded neat at 298 K. Figure A.133. 1H NMR spectrum of (1-phenylethyl)di(3-methylphenyl)silane (4af) recorded in CD3CN at 298 K. 207 Figure A.134. 13C{1H} NMR spectrum of (1-phenylethyl)di(3-methylphenyl)silane (4af) recorded in CD3CN at 298 K. Figure A.135. 29Si{1H} NMR spectrum of (1-phenylethyl)di(3-methylphenyl)silane (4af) recorded in CD3CN at 298 K. 208 Figure A.136. COSY NMR spectrum of (1-phenylethyl)di(3-methylphenyl)silane (4af) recorded in CD3CN at 298 K. Figure A.137. HSQC NMR spectrum of (1-phenylethyl)di(3-methylphenyl)silane (4af) recorded in CD3CN at 298 K. 209 Figure A.138. IR spectrum of (1-phenylethyl)di(3-methylphenyl)silane (4af) recorded neat at 298 K. Figure A.139. 1H NMR spectrum of (1-phenylethyl)di(2-methylphenyl)silane (4ag) recorded in CD3CN at 298 K. 210 Figure A.140. 13C{1H} NMR spectrum of (1-phenylethyl)di(2-methylphenyl)silane (4ag) recorded in CD3CN at 298 K. Figure A.141. 29Si{1H} NMR spectrum of (1-phenylethyl)di(2-methylphenyl)silane (4ag) recorded in CD3CN at 298 K. 211 Figure A.142. COSY NMR spectrum of (1-phenylethyl)di(2-methylphenyl)silane (4ag) recorded in CD3CN at 298 K. Figure A.143. HSQC NMR spectrum of (1-phenylethyl)di(2-methylphenyl)silane (4ag) recorded in CD3CN at 298 K. 212 Figure A.144. IR spectrum of (1-phenylethyl)di(2-methylphenyl)silane (4ag) recorded neat at 298 K. Figure A.145. 1H NMR spectrum of (1-phenylethyl)phenylmesitylsilane (4ah) diastereomers A and B (A/B = 1.1:1) after the first column recorded in CDCl3 at 298 K. 213 Figure A.146. 1H NMR spectrum of (1-phenylethyl)phenylmesitylsilane (4ah) after the second column with diastereomer A as the major species (A/B = 7.1:1) recorded in CDCl3 at 298 K. Figure A.147. 13C{1H} NMR spectrum of (1-phenylethyl)phenylmesitylsilane (4ah) after the second column with diastereomer A as the major species (A/B = 7.1:1) recorded in CDCl3 at 298 K. 214 Figure A.148. COSY NMR spectrum of (1-phenylethyl)phenylmesitylsilane (4ah) after the second column with diastereomer A as the major species (A/B = 7.1:1) recorded in CDCl3 at 298 K. Figure A.149. HSQC NMR spectrum of (1-phenylethyl)phenylmesitylsilane (4ah) after the second column with diastereomer A as the major species (A/B = 7.1:1) recorded in CDCl3 at 298 K. 215 Figure A.150. 1H NMR spectrum of (1-phenylethyl)phenylmesitylsilane (4ah) after the second column with diastereomer B as the major species (A/B = 1:3.8) recorded in CDCl3 at 298 K. Figure A.151. 13C{1H} NMR spectrum of (1-phenylethyl)phenylmesitylsilane (4ah) after the second column with diastereomer B as the major species (A/B = 1:3.8) recorded in CDCl3 at 298 K. 216 Figure A.152. COSY NMR spectrum of (1-phenylethyl)phenylmesitylsilane (4ah) after the second column with diastereomer B as the major species (A/B = 1:3.8) recorded in CDCl3 at 298 K. Figure A.153. HSQC NMR spectrum of (1-phenylethyl)phenylmesitylsilane (4ah) after the second column with diastereomer B as the major species (A/B = 1:3.8) recorded in CDCl3 at 298 K. 217 Figure A.154. 29Si NMR spectrum of (1-phenylethyl)phenylmesitylsilane (4ah) diastereomers A and B (A/B = 1:3.8) after the first column recorded in CDCl3 at 298 K. Figure A.155. IR spectrum of (1-phenylethyl)phenylmesitylsilane (4ah) diastereomers A and B (A/B = 1.1:1) after the first column recorded neat at 298 K. 218 Figure A.156. 1H NMR spectrum of (1-phenylethyl)(2-naphthyl)phenylsilane (4ai) diastereomers A and B (A/B = 1.04:1) after the first column recorded in CDCl3 at 298 K. Figure A.157. 1H NMR spectrum of (1-phenylethyl)(2-naphthyl)phenylsilane (4ai) after the second column with diastereomer A as the major species (A/B = 8.3:1) recorded in CDCl3 at 298 K. 219 Figure A.158. 13C{1H} NMR spectrum of (1-phenylethyl)(2-naphthyl)phenylsilane (4ai) after the second column with diastereomer A as the major species (A/B = 8.3:1) recorded in CDCl3 at 298 K. Figure A.159. COSY NMR spectrum of (1-phenylethyl)(2-naphthyl)phenylsilane (4ai) after the second column with diastereomer A as the major species (A/B = 8.3:1) recorded in CDCl3 at 298 K. 220 Figure A.160. HSQC NMR spectrum of (1-phenylethyl)(2-naphthyl)phenylsilane (4ai) after the second column with diastereomer A as the major species (A/B = 8.3:1) recorded in CDCl3 at 298 K. Figure A.161. 29Si NMR spectrum of (1-phenylethyl)(2-naphthyl)phenylsilane (4ai) after the second column with diastereomer A as the major species (A/B = 8.3:1) recorded in CDCl3 at 298 K. 221 Figure A.162. 1H NMR spectrum of (1-phenylethyl)(2-naphthyl)phenylsilane (4ai) after the second column with diastereomer B as the major species (A/B = 1:4.5) recorded in CDCl3 at 298 K. Figure A.163. 13C{1H} NMR spectrum of (1-phenylethyl)(2-naphthyl)phenylsilane (4ai) after the second column with diastereomer B as the major species (A/B = 1:4.5) recorded in CDCl3 at 298 K. 222 Figure A.164. COSY NMR spectrum of (1-phenylethyl)(2-naphthyl)phenylsilane (4ai) after the second column with diastereomer B as the major species (A/B = 1:4.5) recorded in CDCl3 at 298 K. Figure A.165. HSQC NMR spectrum of (1-phenylethyl)(2-naphthyl)phenylsilane (4ai) after the second column with diastereomer B as the major species (A/B = 1:4.5) recorded in CDCl3 at 298 K. 223 Figure A.166. 29Si NMR spectrum of (1-phenylethyl)(2-naphthyl)phenylsilane (4ai) diastereomers B as the major species (A/B = 1:4.5) after the second column recorded in CDCl3 at 298 K. Figure A.167. IR spectrum of (1-phenylethyl)(2-naphthyl)phenylsilane (4ai) diastereomers A and B (A/B = 1.04:1) after the first column recorded neat at 298 K. 224 Figure A.168. 1H NMR spectrum of (1-phenylethyl)diethylsilane (4aj) recorded in CD3CN at 298 K. Figure A.169. 13C{1H} NMR spectrum of (1-phenylethyl)diethylsilane (4aj) recorded in CD3CN at 298 K. 225 Figure A.170. 29Si NMR spectrum of (1-phenylethyl)diethylsilane (4aj) recorded in CD3CN at 298 K. Figure A.171. IR spectrum of (1-phenylethyl)diethylsilane (4aj) recorded neat at 298 K. 226 Figure A.172. 1H NMR spectrum of (1-phenylethyl)tri(4-methoxyphenyl)silane (4ak) recorded in CD3CN at 298 K. Figure A.173. 13C{1H} NMR spectrum of (1-phenylethyl)tri(4-methoxyphenyl)silane (4ak) recorded in CD3CN at 298 K. 227 Figure A.174. 29Si NMR spectrum of (1-phenylethyl)tri(4-methoxyphenyl)silane (4ak) recorded in CD3CN at 298 K. Figure A.175. COSY NMR spectrum of (1-phenylethyl)tri(4-methoxyphenyl)silane (4ak) recorded in CD3CN at 298 K. 228 Figure A.176. HSQC NMR spectrum of (1-phenylethyl)tri(4-methoxyphenyl)silane (4ak) recorded in CD3CN at 298 K. Figure A.177. IR spectrum of (1-phenylethyl)tri(4-methoxyphenyl)silane (4ak) recorded neat at 298 K. 229 Figure A.178. 1H NMR spectrum of (1-phenylethyl)triphenylsilane (4al) recorded in CDCl3 at 298 K. Figure A.179. 13C{1H} NMR spectrum of (1-phenylethyl)triphenylsilane (4al) recorded in CDCl3 at 298 K. 230 Figure A.180. 29Si NMR spectrum of (1-phenylethyl)triphenylsilane (4al) recorded in CDCl3 at 298 K. Figure A.181. COSY NMR spectrum of (1-phenylethyl)triphenylsilane (4al) recorded in CDCl3 at 298 K. 231 Figure A.182. HSQC NMR spectrum of (1-phenylethyl)triphenylsilane (4al) recorded in CDCl3 at 298 K. Figure A.183. IR spectrum of (1-phenylethyl)triphenylsilane (4al) recorded neat at 298 K. 232 Figure A.184. 1H NMR spectrum of (1-phenylethyl)tri[4-(trifluoromethyl)phenyl]silane (4am) recorded in CDCl3 at 298 K. Figure A.185. 13C{1H} NMR spectrum of (1-phenylethyl)tri[4-(trifluoromethyl)phenyl]silane (4am) recorded in CDCl3 at 298 K. 233 Figure A.186. 19F NMR spectrum of (1-phenylethyl)tri[4-(trifluoromethyl)phenyl]silane (4am) recorded in CDCl3 at 298 K. Figure A.187. 29Si NMR spectrum of (1-phenylethyl)tri[4-(trifluoromethyl)phenyl]silane (4am) recorded in CDCl3 at 298 K. 234 Figure A.188. COSY NMR spectrum of (1-phenylethyl)tri[4-(trifluoromethyl)phenyl]silane (4am) recorded in CDCl3 at 298 K. Figure A.189. HSQC NMR spectrum of (1-phenylethyl)tri[4-(trifluoromethyl)phenyl]silane (4am) recorded in CDCl3 at 298 K. 235 Figure A.190. IR spectrum of (1-phenylethyl)tri[4-(trifluoromethyl)phenyl]silane (4am) recorded neat at 298 K. Figure A.191. 1H NMR spectrum of (1-phenylethyl)diphenylmethylsilane (4an) recorded in CD3CN at 298 K. 236 Figure A.192. 13C{1H} NMR spectrum of (1-phenylethyl)diphenylmethylsilane (4an) recorded in CD3CN at 298 K. Figure A.193. 29Si NMR spectrum of (1-phenylethyl)diphenylmethylsilane (4an) recorded in CD3CN at 298 K. 237 Figure A.194. 1H NMR spectrum of (1-phenylethyl)phenyldimethylsilane (4ao) recorded in CD3CN at 298 K. Figure A.195. 13C{1H} NMR spectrum of (1-phenylethyl)phenyldimethylsilane (4ao) recorded in CD3CN at 298 K. 238 Figure A.196. 29Si NMR spectrum of (1-phenylethyl)phenyldimethylsilane (4ao) recorded in CD3CN at 298 K. Figure A.197. 1H NMR spectrum of (1-phenylethyl)triethoxysilane (4ap) recorded in CDCl3 at 298 K. 239 Figure A.198. 13C{1H} NMR spectrum of (1-phenylethyl)triethoxysilane (4ap) recorded in CDCl3 at 298 K. Figure A.199. 29Si NMR spectrum of (1-phenylethyl)triethoxysilane (4ap) recorded in CDCl3 at 298 K. 240 Figure A.200. IR NMR spectrum of (1-phenylethyl)triethoxysilane (4ap) recorded neat at 298 K. Figure A.201. 1H NMR spectrum of 1,1,1,3,5,5,5-Heptamethyl-3-(1-phenylethyl)trisiloxane (4aq) recorded in CDCl3 at 298 K. 241 Figure A.202. 13C{1H} NMR spectrum of 1,1,1,3,5,5,5-Heptamethyl-3-(1- phenylethyl)trisiloxane (4aq) recorded in CDCl3 at 298 K. Figure A.203. 29Si NMR spectrum of 1,1,1,3,5,5,5-Heptamethyl-3-(1-phenylethyl)trisiloxane (4aq) recorded in CDCl3 at 298 K. 242 Figure A.204. COSY NMR spectrum of 1,1,1,3,5,5,5-Heptamethyl-3-(1- phenylethyl)trisiloxane (4aq) recorded in CDCl3 at 298 K. Figure A.205. HSQC NMR spectrum of 1,1,1,3,5,5,5-Heptamethyl-3-(1- phenylethyl)trisiloxane (4aq) recorded in CDCl3 at 298 K. 243 Figure A.206. IR NMR spectrum of 1,1,1,3,5,5,5-Heptamethyl-3-(1-phenylethyl)trisiloxane (4aq) recorded neat at 298 K. Figure A.207. 1H NMR spectrum of (1-phenylethyl)trichlorosilane (4ar) recorded in CDCl3 at 298 K. 244 Figure A.208. 13C{1H} NMR spectrum of (1-phenylethyl)trichlorosilane (4ar) recorded in CDCl3 at 298 K. Figure A.209. 29Si NMR spectrum of (1-phenylethyl)trichlorosilane (4ar) recorded in CDCl3 at 298 K. 245 Figure A.210. COSY NMR spectrum of (1-phenylethyl)trichlorosilane (4ar) recorded in CDCl3 at 298 K. Figure A.211. HSQC NMR spectrum of (1-phenylethyl)trichlorosilane (4ar) recorded in CDCl3 at 298 K. 246 Figure A.112. IR spectrum of (1-phenylethyl)trichlorosilane (4ar) recorded neat at 298 K. Figure A.113. 1H NMR spectrum of (1-phenylethyl)dichloromethylsilane (4as) recorded in CDCl3 at 298 K. 247 Figure A.114. 13C{1H} NMR spectrum of (1-phenylethyl)dichloromethylsilane (4as) recorded in CDCl3 at 298 K. Figure A.115. 29Si NMR spectrum of (1-phenylethyl)dichloromethylsilane (4as) recorded in CDCl3 at 298 K. 248 Figure A.116. COSY NMR spectrum of (1-phenylethyl)dichloromethylsilane (4as) recorded in CDCl3 at 298 K. Figure A.117. HSQC NMR spectrum of (1-phenylethyl)dichloromethylsilane (4as) recorded in CDCl3 at 298 K. 249 Figure A.118. IR NMR spectrum of (1-phenylethyl)dichloromethylsilane (4as) recorded neat at 298 K. 250 APPENDIX B SUPPLEMENTARY CONTENT FOR CHAPTER III Experimental details B.1.1. Materials and Methods All syntheses and manipulations were carried out under nitrogen using standard Schlenk (vacuum 10-2 mbar) techniques or in a nitrogen-filled glovebox unless otherwise indicated. All reagents and solvents were used after drying and stored under nitrogen, unless otherwise indicated. Tetrahydrofuran (THF; Fisher Chemical; HPLC grade, unstabilized), hexanes (Fisher Chemical; HPLC grade), diethyl ether (B&J Brand; HPLC grade, unstabilized) and acetonitrile (Fisher Chemical; HPLC grade) were dispensed under nitrogen from an LC Technology SP-1 solvent system. Benzene (ACS grade) and pentane (HPLC grade) were refluxed overnight with CaH2 and distilled under nitrogen before use. The dried solvents were thereafter stored on activated 4Å molecular sieves under nitrogen. CD3CN, C6D6 and CDCl3 were purchased from Cambridge Isotope Laboratories, degassed by freeze-pump-thaw, and thereafter stored on activated 4Å molecular sieves under nitrogen. All stock solutions were prepared by mass and were dispensed into the reaction vessel by difference from syringe, as detailed in the procedure for each experiment. The following reagents were used from commercial sources without further purification: lithium aluminum deuteride (Aldrich Chemical), styrene-d8 (2a-d8; Fisher Scientific), 4- methoxystyrene (2c; Alfa Aesar), 4-methylstyrene (2e; TCI), 4-fluorostyrene (2f; Matrix), 2- methylstyrene (2h; TCI), durene (Eastman Chemical Company), and 1,3,5-trimethoxybenzene (TCI). 2s and DPE were synthesized via reported procedures.6,125 B.1.2. General Experimental Nuclear magnetic resonance (NMR) spectra were collected at room temperature (298 K) unless otherwise stated on a Bruker AV-III HD 600 NMR (600.13 MHz for 1H; 150.90 MHz for 13C; 564.69 MHz for 19F; 119.23 MHz for 29Si; 92.12 MHz for 2H), Bruker Avance-III HD 500 NMR (499.90 MHz for 1H; 126 MHz for 13C; 471 MHz for 19F; 99 MHz for 29Si), or Varian Inova 500 NMR (499.90 MHz for 1H; 126 MHz for 13C; 471 MHz for 19F; 99 MHz for 29Si). 1H and 13C 251 spectra were referenced to the residual solvent peak (CDCl 13: H δ = 7.26 ppm, 13C δ = 77.16 ppm; C6D6: 1H δ = 7.16 ppm, 13C δ = 128.06 ppm, CD3CN: 1H δ = 1.94 ppm, 13C δ = 1.32 ppm (NCCD3)). Chemical shifts for 1H, 13C, and 29Si NMR spectra are reported in parts per million (ppm, δ) relative to tetramethylsilane at 0.00 ppm. Peaks are characterized as follows: s (singlet), d (doublet), t (triplet), q (quartet), pent (pentet), hept (heptet), m (multiplet), qd (quartet of doublets), br (broad), app (apparent), and/or ms (multiple signals). Coupling constants, J, are reported in Hz. 1JH–Si coupling constants were determined, when possible, using the 29Si satellites in the 1H NMR spectrum. Infrared (IR) spectroscopy for air-stable organic compounds was performed on an Agilent Nicolet 6700 FT-IR using the ATR sampling technique. IR spectra for air-sensitive nickel complexes were recorded as self-supported pellets diluted with KBr using a Bruker Alpha II FT- IR spectrometer that is housed in a nitrogen-filled glovebox. All bands are reported in wavenumbers (cm-1) and are described as broad (br), strong (s), medium (m), and weak (w). B.1.3. Synthesis of 3a-d2 d. Diphenylsilane-d2 (3a-d2) was synthesized via a modified literature procedure: 276 An oven-dried Schlenk flask equipped with a magnetic stir bar was charged with Cl2SiPh2 (2.0 mL, 9.5 mmol, 1.3 equiv) and Et2O (18 mL). LiAlD4 (0.30 g, 7.2 mmol, 1.0 equiv) was added to the stirring reaction, and the reaction was heated to reflux for 24 h. The reaction was then cooled to room temperature and quenched with the slow addition of water until all fizzing ceased. The remaining solution was filtered through Celite and washed with Et2O (5 mL). The aqueous layer was separated and extracted with Et2O (3 x 20 mL). The organic layers were combined and dried over MgSO4. The solids were filtered off and the filtrate was concentrated under reduced pressure to yield a pale-yellow oil. The crude product was purified by filtering through silica and eluting with hexanes. The filtrate was concentrated under reduced pressure to yield 3a-d2 as a clear, colorless oil (0.758 g, 4.07 mmol, 57% yield). NMR spectra match values previously reported.276 The 252 density of 3a-d2 was determined by measuring 10 μL of sample using a 25-μL syringe and measuring the weight of the sample; this was repeated three times, and the average of the three trials was found to be 1.0 ± 0.1 g/mL. B.1.4. Monitoring Hydrosilylation of styrene (2a) and d2-diphenylsilane by 2H NMR In a nitrogen-filled glovebox, 1e (7.5 mg, 0.013 mmol, 0.10 equiv) was added to a J-Young NMR tube and solvated in 9:1 C7H8/C7D8 (0.60 mL, 0.22 M), which was added using disposable 1-mL syringes. To this solution was added 2a (17 μL, 0.14 mmol, 1.0 equiv) and 3a-d2 (28 μL, 0.15 mmol, 1.1 equiv) using a 50-μL syringe. The NMR tube was sealed, brought out of the glovebox, and placed into the NMR (Bruker AV-III HD 600), which had been preheated to 75 °C. Reaction progress was monitored by 2H NMR over time. Qualitative analysis of the formation of 4aa-d2 was determined by the appearance of peaks that correspond to 2c (doublet of doublet at 5.57 ppm), 3a-d2 (singlet at 5.03 ppm), 4aa-d2 (broad singlet at 5.01 ppm, broad multiplet at 2.66, and broad doublet at 1.37 ppm), and 1e (broad multiplet at 2.60 ppm). B.1.5. Deuterium Incorporation and Crossover Experiments a. Deuterium Labelling Study using D2SiPh2 In a nitrogen-glovebox, 1e (3.7 mg, 0.0065 mmol, 0.050 equiv) was weighed out into a J- Young NMR tube and solvated in C7D8 (0.60 mL, 0.22 M), which was added using a disposable 1-mL syringe. To this solution was added 2a (15 μL, 0.13 mmol, 1.0 equiv), 3a-d2 (27 μL, 0.14 mmol, 1.1 equiv) and mesitylene (4.5 μL, 0.032 mmol). The NMR tube was sealed, brought out of the glovebox, and placed onto a preheated oil bath at 100 °C. After 4 h, the reaction was 253 quenched in a liquid N2 bath, thawed, and analyzed by 1H NMR. For 2H NMR, the sample was concentrated under vacuum and redissolved in 1:5 C D :C H . 27 8 7 8 H NMR shows deuterium incorporation in three positions with calculated amounts: Da = 44%, Db = 3%, Dc = 45%. Calculations for Da and Dc are based on the relative integration of the respective peaks against the C(aryl)–Hd (7.33 ppm, d, 2H) in the 1H NMR. This calculation assumes that no D incorporation occurs at the C(aryl)–Hd position, which is confirmed in the 2H NMR spectrum (Figure S16). Because of overlapping peaks, integration of the benzylic position (H/Db) are not reliable. To determine the D incorporation at this site, relative integrations of the Da and D 2 b position in the H NMR were used. Figure B.1. 1H NMR spectrum of 4aa-dn after the hydrosilylation of 2a and 3a-d2 recorded in C7D8 at 25 °C. 254 Figure B.2. 2H NMR spectrum of 4aa-dn after hydrosilylation of 2a with 3a-d2 recorded in 1:5 C7D8:C7H8 at 25 °C. b. Deuterium Labelling Study Using Styrene-d8 (2a-d8) In a nitrogen-glovebox, 1e (3.7 mg, 0.0065 mmol, 0.050 equiv) was weighed out into a J- Young NMR tube and solvated in C7D8 (0.60 mL, 0.22 M), which was added using a disposable 1-mL syringe. To this solution was added styrene-d8 (15 L, 0.13 mmol, 20. equiv.), 3a (27 µL, 0.14 mmol, 1.1 equiv) and mesitylene (5.0 µL, 0.036 mmol). The NMR tube was sealed and placed onto a preheated oil bath at 100 °C. After 4 h, the reaction was quenched in a liquid N2 bath, thawed, and analyzed by 1H NMR. For 2H NMR, the sample was concentrated under reduced pressure and redissolved in 1:9 C7D8:C7H8. 2H NMR shows deuterium incorporation in three 255 positions with calculated amounts: Da = 34%, Db = 70%, Dc = 46%. Calculations for Da, Db, and Dc are based on the relative integration of the respective peaks against the C(aryl)–Hd (7.33 ppm, d, 2H) in the 1H NMR. This calculation assumes that no D incorporation occurs at the C(aryl)–Hd position, which is confirmed in the 2H NMR spectrum (Figure S18). Figure B.3. 1H NMR spectrum of crude reaction after heating the hydrosilylation reaction of styrene-d8 and 3a at 100 °C for 4 h. Recorded in C7D8 at 25 °C. 256 Figure B.4. 2H NMR spectrum of 4aa-dn after hydrosilylation of d8-styrene with 3a recorded in 1:9 C7D8:C7H8 at 25 °C. c. Crossover Experiment In a nitrogen-filled glovebox, 1e (3.9 mg, 0.0068 mmol, 0.050 equiv) was weighed out into a J-Young NMR tube and solvated in C7D8 (0.60 mL, 0.22 M), which was added using a disposable 1-mL syringe. To this solution was added 2a (15 µL, 0.13 mmol, 1.0 equiv), 3a-d2 (14 µL, 0.072 257 mmol, 0.56 equiv), 3b (18 mg, 0.072 mmol, 0.56 equiv) and mesitylene (5.0 µL, 0.036 mmol). The NMR tube was sealed, brought out of the glovebox, and placed onto a preheated oil bath at 100 °C. After 4 h, the reaction was quenched in a liquid N2 bath, thawed, and analyzed by 1H NMR. For 2H NMR, the sample was concentrated under reduced pressure and redissolved in 1:5 C7D8:C7H8. Complete scrambling between 4aa and 4ac was observed for all three H/D positions labelled below. Figure B.5. 1H NMR spectrum of the crossover between 3a-d2 and 3b with 2a to form 4aa-dn and 4ab-dn recorded in C7D8 at 25 °C. 258 Figure B.6. 2H NMR spectrum of the crossover of 3a-d2 and 3b with 2a to afford 4aa-dn and 4ab- dn recorded in 1:5 C7D8:C7H8 at 25 °C. B.1.6. Kinetics Experiments a. Kinetic Isotope Effects In a nitrogen-filled glovebox, a stock solution of 1e (37 mg, 0.65 mmol) was prepared in toluene (2.0 mL) using volumetric glassware and distributed (0.40 mL) using a disposable 1-mL syringe to four 1-dram vials equipped with stir bars. To each vial was added 2a (30 μL, 0.26 mmol, 1.0 equiv), and mesitylene (20 μL, 0.14 mmol) using a 50-μL syringe. Additional toluene (0.80 259 mL) was added to each vial using a disposable 1-mL syringe to obtain a final reaction concentration of 0.22 M. The vial was sealed with a septum cap, brought out of the glovebox, injected with 3a (54 μL, 0.29 mmol, 1.1 equiv) or 3a-d2 (54 μL, 0.29 mmol, 1.1 equiv), and placed on an aluminum vial block preheated to 80 °C. Throughout the course of the reaction, 20 μL aliquots were removed with a 25-μL syringe, filtered into a GC vial through Celite, and diluted with hexanes. The filtrate from the Celite plug was analyzed by GC to assess the reaction progress and selectivity. The product concentration was determined by relative integration (by GC) of the product peaks against mesitylene, in accordance with a calibration curve. 30 25 y = (2.46±0.08)x R² = 0.9931 20 D2SiPh2 15 10 H2SiPh2 y = (1.59±0.08)x 5 R² = 0.9845 0 0 2 4 6 8 10 12 Time (min) Figure B.7. Initial rates of the formation of 4aa-dn versus time (min). 260 [4aa-dn] (mM) 250 200 D2SiPh2 150 H2SiPh2 100 50 0 0 50 100 150 200 250 Time (min) Figure B.8. Full kinetic profile of the formation of 4aa-dn versus time (min). Table B.1. Formation of 4aa-dn over time with 3a or 3a-d2. Reaction with 3a Reaction with 3a-d2 Time (min) [4aa] (mM) Selectivity (l/b) [4aa-d2] (mM) Selectivity (l/b) 1 1.1 ± 0.3 1:1.9 1.7 ± 0.5 1:1.5 2 2 ± 1 1:3.2 4.0 ± 0.1 1:6.4 3 3.7 ± 0.5 1:6.2 6.3 ± 0.4 1:37 4 5.7 ± 0.7 1:7.4 9.26 ± 0.08 1:17 5 7.1 ± 0.4 1:7.3 12.0 ± 0.7 1:34 6 9.5 ± 0.5 1:8.8 13.46 ± 0.07 1:30 10 17.4 ± 0.5 1:9.5 26 ± 4 1:28 20 38 ± 2 1:9.0 53 ± 4 1:19 30 51 ± 3 1:8.3 79.4 ± 0.2 1:22 40 86 ± 1 1:7.4 107.99 ± 0.02 1:22 60 120 ± 10 1:7.0 157 ± 5 1:20 80 150 ± 12 1:7.1 215 ± 7 1:22 100 180 ± 16 1:7.4 237.4 ± 0.4 1:21 120 206 ± 4 1:8.6 233 ± 2 1:23 150 210 ± 11 1:8.6 228 ± 7 1:25 180 216 ± 2 1:8.3 231 ± 4 1:20 240 220 ± 2 1:8.4 231 ± 6 1:22 261 [4aa-dn] (mM) b. Eyring Plot In a nitrogen-filled glovebox, 1e (7.6 mg, 0.013 mmol, 0.050 equiv) was weighed out into a 1-dram scintillation vial equipped with a stir bar. Toluene (1.2 mL) was added to each vial using a disposable 1-mL syringe, followed by 2a (30 µL, 0.26 mmol, 1.0 equiv) and mesitylene (20 µL, 0.14 mmol) using a 50-µL syringe. The vial was sealed with a septum cap, brought out of the glovebox, injected with 3a (54 µL, 0.29 mmol, 1.1 equiv), and placed on an aluminum vial block preheated to 333 K, 343 K, 353 K, or 373 K. Throughout the course of the reaction, 20 µL aliquots were removed with a 25-µL syringe, diluted with hexanes, and filtered through Celite into a GC vial. The filtrate from the Celite plug was analyzed by GC to assess the reaction progress and selectivity. Product concentration was determined by relative integration (by GC) of the product peaks against the internal standard, mesitylene, in accordance with a calibration curve. Two trials were run for all temperatures except for the reaction run at 353 K, at which only one trial was run. Table B.2. Formation of 4aa over time at varying reaction temperatures. Temperature Time (min) [4aa] (mM) Selectivity (l/b) 5 2.42 ± 0.02 1:7.3 10 3.3 ± 0.7 1:4.8 15 4.7 ± 0.7 1:5.4 20 5.21 ± 0.03 1:4.3 30 7.7 ± 0.5 1:3.9 44 11.2 ± 0.7 1:3.3 333 K 61 17.9 ±0.4 1:3.1 80 22 ± 2 1:2.8 100 30 ± 5 1:2.6 120 37 ± 3 1:2.3 190 70 ± 1 1:2.0 243 97 ± 8 1:1.8 337 132 ± 5 1:1.5 262 1 0.67 0:1.0 2 2.0 ± 0.8 1:13 3 2.5 ± 0.4 1:11 4 3.4 ± 0.7 1:17 5 4.25 ± 0.05 1:7.8 7 5.8 ± 0.5 1:7.2 10 9 ± 2 1:11 15 13.08 ± 0.09 1:7.0 343 K 20 19 ± 2 1:7.0 30 27 ± 4 1:5.1 47 50 ± 9 1:4.1 60 56 ± 3 1:3.7 80 80 ± 11 1:3.1 90 122 ± 17 1:2.7 120 132 ± 3 1:2.7 148 150 ± 4 1:2.5 202 169 ± 4 1:2.7 1 1.8 1:7.6 2 3.4 1:10 3 4.8 1:11 4 6.4 1:6.9 5 9.2 1:11 6 10 1:7.7 8 14 1:8.8 10 16 1:8.8 353 K 15 30 1:7.5 20 37 1:6.5 33 64 1:5.7 64 141 1:5.0 90 189 1:6.0 129 184 1:6.1 170 175 1:6.1 240 170 1:6.7 0.5 1 ± 1 1:1.7 1.0 5 ± 1 1:3.0 1.7 14 ± 3 1:12 373 K 2.2 20 ± 1 1:11 3.5 37 ± 3 1:13 4.0 42 ± 6 1:12 263 5.0 57 ± 5 1:14 6.0 78 ± 14 1:14 7.0 100 ± 13 1:14 10 138 ± 2 1:15 15 218 ± 7 1:17 30 231 ± 13 1:19 60 234 ± 8 1:18 120 225 ± 3 1:18 180 227 ± 6 1:18 240 227 ± 8 1:18 30 y = (8±1)x y = (1.69±0.03)x y = (0.91±0.02)x y = (0.275±0.007)x R² = 0.9582 R² = 0.9981 R² = 0.9958 R² = 0.996 25 20 15 10 373 K 353 K 5 343 K 333 K 0 0 20 40 60 80 Time (min) Figure B.9. Initial rates for the formation of 4aa over time (min) at varying temperatures. 264 [4aa] mM 250 200 150 100 50 373 K 353 K 343 K 333 K 0 0 50 100 150 200 250 Time (min) Figure B.10. Full kinetic profile for the formation of 4aa over time (min) at varying temperatures. Table B.3. Rates of formation of 4aa at varying temperatures. Temperature (K) 1/K (T-1) Δ[4aa]/Δt (mM/min) ln([(Δ[4aa]/Δt)·T–1]) 333 0.00268 0.275 ± 0.007 -7.10 ± 0.02 343 0.00283 0.91 ± 0.02 -5.94 ± 0.02 353 0.00292 1.69 ± 0.03 -4.34 ± 0.08 373 0.003003 8 ± 1 -3.8 ± 0.1 To construct the Eyring plot, ln([(Δ[4aa]/Δt)·T–1]) was plotted as a function of 1/T. Using Microsoft Excel, the data were fit to a curve for the function y = mx + b, where y = ln[(Δ[4aa]/Δt)·T–1] input, m = –ΔH•R-1 output, x = T-1 input, and b = ΔS•R-1+ln(kB/h) output, as illustrated below. Δ[𝟒𝐚𝐚]/Δt −Δ𝐻‡ 1 −Δ𝑆‡ kB ln ( ) = ( ) ( ) + ( ) + ln T R T R h Where… R = 0.001987 kcal•mol-1•K- (Ideal gas constant) 1 kB = 1.38x10 -23 J•K-1 (Boltzmann constant) h = 6.63x10-34 J•s (Planck’s constant) 265 [4aa] mM Gibbs free energy of activation was determined using the following equation: ∆𝐺‡ = ∆𝐻‡ ‒ 𝑇∆𝑆‡ -3 y = -9964.4x + 22.932 -4 R² = 0.9914 -5 -6 -7 -8 0.0026 0.0027 0.0028 0.0029 0.003 0.0031 1/T (K-1) Figure B.11. Eyring plot. ΔH‡ = 20.4 ± 0.2 kcal•mol-1 ΔS‡ = -0.28 ± 0.2 cal•mol-1•K-1 ΔG‡373K = 20.5 ± 0.2 kcal•mol -1 c. Rate Law In a nitrogen-filled glovebox, a stock solution of 1e, 2a, and mesitylene was prepared and distributed into 1-dram vials equipped with stir bars using a disposable 1 mL-syringe. The vial was sealed with a septum cap, brought out of the glovebox, injected with the corresponding amount of 3a, and placed on an aluminum vial block preheated to 80 °C. Throughout the course of the reaction, 20 μL aliquots were removed with a 25-μL syringe and filtered into a GC vial through Celite and diluted with hexanes. The filtrate was analyzed by GC to assess the reaction progress and selectivity. The product concentration was determined by relative integration (by GC) of the 266 ln(Δ[4aa]/Δt)/T) product peaks against mesitylene, in accordance with calibration curves. Two trials were run for all experiments. Table B.4. Amounts and concentrations of 1e, 2a, 3a (mM) and observed rate determined by initial rates. Entry [1e] (mM) [2a] (mM) [3a] (mM) Rate (mM/min) 1 2.19 218 242 0.79 ± 0.02 2 5.47 218 242 1.36 ± 0.06 3* 10.9 218 242 1.59 ± 0.08 4 21.9 218 242 3.37 ± 0.09 5 10.9 436 242 1.33 ± 0.04 6 10.9 1091 242 0.660 ± 0.007 7 10.9 2182 242 0.74 ± 0.03 8 10.9 218 26.9 0.18 ± 0.01 9 10.9 218 58.4 0.44 ± 0.04 10 10.9 218 121 1.13 ± 0.04 *These are the standard conditions. See data in “Kinetics to Measure KIE” section B.1.6.a for values (Figures B.7.-B.8., Table B.1.). 35 2.19 mM 1e 30 y = (0.75±0.02)x 25 R² = 0.9954 20 15 10 5 0 0 5 10 15 20 25 30 35 Time (min) Figure B.12. Table B.4., Entry 1: Initial rate of formation of 4aa with 2.19 mM 1e, 218 mM 2a, and 242 mM 3a. 267 [4aa] (mM) 300 2.19 mM 1e 250 200 150 100 50 0 0 100 200 300 400 Time (min) Figure B.13. Table B.4., Entry 1: Full reaction profile for the formation of 4aa over time (min) with 2.19 mM 1e, 218 mM 2a, and 242 mM 3a. 268 [4aa] (mM) Table B.5. Table B.4., Entry 1: [4aa] (mM) and selectivity (l:b) of 4aa formed with 2.19 mM 1e, 218 mM 2a, and 242 mM 3a. Time (min) [4aa] (mM) Selectivity (l:b) 1 0.94 ± 0.09 1:1.4 2 1.987 ± 0.006 1:1.1 3 2.8 ± 0.4 1:1.5 4 3.6 ± 0.1 1:1.5 6 5.3 ± 0.4 1:1.8 8 6.71 ± 0.08 1:1.9 10 8.5 ± 0.4 1:2.0 20 15 ± 3 1:2.2 32 22.9 ± 0.8 1:2.4 45 31.7 ± 0.7 1:2.7 60 43 ± 1 1:2.3 90 61.7 ± 0.5 1:2.2 120 84 ± 2 1:2.1 153 113 ± 14 1:1.9 180 140 ± 32 1:1.9 253 172.7 ± 0.9 1:1.9 300 160 ± 16 1:2.0 360 167 ± 5 1:2.0 35 5.47 mM 1e 30 25 20 15 y = (1.38±0.03)x 10 R² = 0.9956 5 0 0 5 10 15 20 Time (min) Figure B.14. Table B.4., Entry 2: Initial rate of formation of 4aa with 5.47 mM 1e, 218 mM 2a, and 242 mM 3a. 269 [4aa] (mM) 300 5.47 mM 1e 250 200 150 100 50 0 0 100 200 300 400 Time (min) Figure B.15. Table B.4., Entry 2: Full reaction profile for the formation of 4aa over time (min) with 5.47 mM 1e, 218 mM 2a, and 242 mM 3a. Table B.6. Table B.4., Entry 2: [4aa] (mM) and selectivity (l:b) of 4aa formed with 5.47 mM 1e, 218 mM 2a, and 242 mM 3a. Time (min) [4aa] (mM) Selectivity (l/b) 1 1.6 ± 0.1 1:1.1 2 2.9 ± 0.2 1:1.5 3 3.9 ± 0.2 1:2.0 4 5.5 ± 0.3 1:2.2 6 7.2 ± 0.2 1:2.7 7 8 ± 2 1:4.4 10 15.0 ± 0.6 1:3.3 18 25.1 ± 0.8 1:3.7 30 42.9 ± 0.6 1:4.1 45 64.2 ± 0.2 1:4.2 60 60 ± 18 1:3.2 90 118 ± 7 1:4.1 117 168.51 ± 0.09 1:4.0 168 210 ± 4 1:4.6 240 203 ± 9 1:4.5 300 204.3 ± 0.9 1:4.7 360 208 ± 7 1:4.6 270 [4aa] (mM) 35 21.9 mM 1e 30 25 20 15 10 y = (3.37±0.09)x 5 R² = 0.993 0 0 1 2 3 4 5 6 7 Time (min) Figure B.16. Table B.4., Entry 4: Initial rate of the formation of 4aa versus time (min) with 21.9 mM 1e, 218 mM 2a, and 242 mM 3a. 300 21.9 mM 1e 250 200 150 100 50 0 0 50 100 150 200 250 300 350 Time (min) Figure B.17. Table B.4., Entry 4: Full reaction profile for the formation of 4aa over time (min) with 21.9 mM 1e, 218 mM 2a, and 242 mM 3a. 271 [4aa] (mM) [4aa] (mM) Table B.7. Table B.4., Entry 4: [4aa] (mM) and selectivity (l:b) of 4aa formed with 21.9 mM 1e, 218 mM 2a, and 242 mM 3a. Time (min) [4aa] (mM) Selectivity (l:b) 0.5 2.1 ± 0.2 1:0.6 1 1.98 ± 0.09 1:2.3 1.7 3.975 ± 0.008 1:4.0 2.5 7.50 ± 0.01 1:3.7 3 10 ± 1 1:5.9 3.5 11.4 ± 0.1 1:6.8 4 13 ± 1 1:6.7 4.5 14.2 ± 0.3 1:9.0 5 17 ± 1 1:8.1 6 22.0 ± 0.4 1:9.9 8 32.9 ± 0.5 1:9.8 15 58.2 ± 0.9 1:14 26 113.4 ± 0.7 1:15 40 180 ± 12 1:18 60 237 ± 2 1:22 90 238 ± 1 1:23 120 232 ± 8 1:23 150 237 ± 3 1:24 224 238 ± 2 1:26 330 237 ± 1 1:27 35 y = (3.37±0.09)x y = (1.59±0.08)x y = (1.38±0.03)x 30 R² = 0.993 R² = 0.9845 R² = 0.9956 25 20 y = (0.75±0.02)x 15 R² = 0.9939 10 Entry 4: 21.9 mM 1e Entry 3: 10.9 mM 1e 5 Entry 2: 5.47 mM 1e Entry 1: 2.19 mM 1e 0 0 10 20 30 40 Time (min) Figure B.18. Table B.4., Entry 1-4: Initial rates of the formation of 4aa with 2.19, 5.47, 10.9, and 21.9 mM 1e (all with 218 mM 2a, 242 mM 3a). 272 [4aa] (mM) 300 250 200 150 100 Entry 4: 21.9 mM 1e Entry 3: 10.9 mM 1e 50 Entry 2: 5.47 mM 1e Entry 1: 2.19 mM 1e 0 0 50 100 150 200 250 300 350 Time (min) Figure B.19. Table B.4., Entry 1-4: Full reaction profile for the formation of 4aa over time (min) with 2.19, 5.47, 10.9, and 21.9 mM 1e (all with 218 mM 2a, 242 mM 3a). 5 4 y = 0.4528x(0.6±0.1) R² = 0.9364 3 2 1 0 0 5 10 15 20 25 [1e] (mM) Figure B.20. Plot of Δ[4aa]/Δt (mM/min) versus [1e] (mM). 273 [4aa] (mM) Δ[4aa]/Δt (mM/min) 30 436 mM 2a 25 y = (1.33±0.04)x R² = 0.9967 20 15 10 5 0 0 5 10 15 20 Time (min) Figure B.21. Table B.4., Entry 5: Initial rate of the formation of 4aa versus time (min) with 10.9 mM 1e, 436 mM 2a, and 242 mM 3a. 300 436 mM 2a 250 200 150 100 50 0 0 100 200 300 400 Time (min) Figure B.22. Table B.4., Entry 5: Full reaction profile for the formation of 4aa over time (min) with 10.9 mM 1e, 436 mM 2a, and 242 mM 3a. 274 [4aa] (mM) [4aa] (mM) Table B.8. Table B.4., Entry 5: [4aa] (mM) and selectivity (l:b) of 4aa formed with 10.9 mM 1e, 436 mM 2a, and 242 mM 3a. Time (min) [4aa] (mM) Selectivity (l:b) 4 3.9 ± 0.7 1:10.1 8 10.0 ± 0.5 1:6.2 12 16.7 ± 0.5 1:5.4 16 21 ± 1 1:5.2 20 56 ± 40 1:9.2 40 59 ± 2 1:4.3 60 90 ± 8 1:3.9 90 128 ± 5 1:3.4 120 170 ± 16 1:3.1 150 191 ± 6 1:2.9 180 206 ± 7 1:2.8 210 228 ± 3 1:2.7 240 230 ± 2 1:2.7 270 210 ± 36 1:2.7 300 220 ± 28 1:2.7 369 191 ± 8 1:2.6 30 1091 mM 2a 25 20 y = (0.660±0.007)x R² = 0.9995 15 10 5 0 0 5 10 15 20 25 Time (min) Figure B.23. Table B.4., Entry 6: Initial rate of the formation of 4aa versus time (min) with 10.9 mM 1e, 1091 mM 2a, and 242 mM 3a. 275 [4aa] (mM) 300 1091 mM 2a 250 200 150 100 50 0 0 100 200 300 400 Time (min) Figure B.24. Table B.4., Entry 6: Full reaction profile for the formation of 4aa over time (min) with 10.9 mM 1e, 1091 mM 2a, and 242 mM 3a. Table B.9. Table B.4., Entry 6: [4aa] (mM) and selectivity (l:b) of 4aa formed with 10.9 mM 1e, 1091 mM 2a, and 242 mM 3a. Time (min) [4aa] (mM) Selectivity (l:b) 4 2.5 ± 0.4 1:2.2 8 5.4 ± 0.3 1:2.4 12 8.0 ± 0.8 1:3.5 16 10.9 ± 0.9 1:3.1 20 13.0 ± 0.4 1:2.9 40 31 ± 1 1:2.2 60 52 ± 6 1:1.9 90 85.0 ± 0.8 1:1.6 120 116 ± 3 1:1.5 150 133 ± 5 1:1.4 180 150 ± 20 1:1.4 210 162 ± 5 1:1.3 240 165 ± 8 1:1.3 270 175 ± 3 1:1.3 300 198 ± 3 1:1.3 369 150 ± 10 1:1.3 276 [4aa] (mM) 30 2182 mM 2a 25 20 15 y = (0.74±0.03)x 10 R² = 0.9929 5 0 0 5 10 15 20 25 30 35 Time (min) Figure B.25. Table B.4., Entry 7: Initial rate of the formation of 4aa versus time (min) with 10.9 mM 1e, 2182 mM 2a, and 242 mM 3a. 300 2182 mM 2a 250 200 150 100 50 0 0 100 200 300 400 500 Time (min) Figure B.26. Table B.4., Entry 7: Full reaction profile for the formation of 4aa over time (min) with 10.9 mM 1e, 2182 mM 2a, and 242 mM 3a. Table B.10. Table B.4., Entry 7: [4aa] (mM) and selectivity (l:b) of 4aa formed with 10.9 mM 1e, 2182 mM 2a, and 242 mM 3a. Time (min) [4aa] (mM) Selectivity (l:b) 277 [4aa] (mM) [4aa] (mM) 4 3 ± 2 1:2.3 8 8 ± 5 1:2.1 12 7.5 ± 0.3 1:2.9 16 12 ± 2 1:3.0 20 14 ± 1 1:2.2 30 23 ± 1 1:2.0 40 37 ± 2 1:1.8 60 51 ± 5 1:1.6 90 82 ± 3 1:1.4 120 109.6 ± 0.4 1:1.4 180 140 ± 16 1:1.4 210 139 ± 2 1:1.4 240 140 ± 8 1:1.4 270 143 ± 2 1:1.4 300 149 ± 3 1:1.4 460 160 ± 14 1:1.5 30 y = (1.33±0.04)x y = (0.74±0.03)x R² = 0.9967 R² = 0.9929 25 y = (1.59±0.08)x 20 R² = 0.9845 15 y = (0.660±0.007)x R² = 0.9995 10 Entry 3: 218 mM 2a Entry 5: 436 mM 2a 5 Entry 6: 1091 mM 2a Entry 7: 2182 mM 2a 0 0 5 10 15 20 25 30 35 Time (min) Figure B.27. Table B.4., Entry 3, 5-7: Initial rates of the formation of 4aa versus time (min) with 218, 436, 1091, and 2182 mM 2a (all with 10.9 mM 1e, 242 mM 3a). 278 [4aa] (mM) 300 250 200 150 100 Entry 3: 218 mM 2a Entry 5: 436 mM 2a 50 Entry 6: 1091 mM 2a Entry 7: 2182 mM 2a 0 0 100 200 300 400 500 Time (min) Figure B.28. Table B.4., Full reaction profile for the formation of 4aa over time (min) 218, 436, 1091, and 2182 mM 2a (all with 10.9 mM 1e, 242 mM 3a). 5 4 3 y = 14.656x(-0.4±0.1) R² = 0.9093 2 1 0 0 500 1000 1500 2000 2500 [2a] (mM) Figure B.29. Table B.4., Plot of Δ[4aa]/Δt (mM/min) versus [2a] (mM). Error bars are present but are not visible. 279 Δ[4aa]/Δt (mM/min) [4aa] (mM) 30 26.9 mM 3a 25 20 15 10 y = (0.18±0.01)x R² = 0.9828 5 0 0 5 10 15 20 Time (min) Figure B.30. Table B.4., Entry 8: Initial rate of the formation of 4aa versus time (min) with 10.9 mM 1e, 218 mM 2a, and 26.9 mM 3a. Error bars are present but are not visible. 300 26.9 mM 3a 250 200 150 100 50 0 0 50 100 150 200 250 300 Time (min) Figure B.31. Table B.4., Entry 8: Full reaction profile for the formation of 4aa over time (min) with 10.9 mM 1e, 218 mM 2a, and 26.9 mM 3a. Error bars are present but are not visible. Table B.11. Table B.4., Entry 8: [4aa] (mM) and selectivity (l:b) of 4aa formed with 10.9 mM 1e, 218 mM 2a, and 26.9 mM 3a. 280 [4aa] (mM) [4aa] (mM) Time (min) [4aa] (mM) Selectivity (l:b) 3 0.9±0.4 1:7.2 5 0.9±0.4 1:6.1 10 1.7±0.3 1:12 15 2.5±0.2 1:19 20 3.3±0.4 1:18 30 5±1 1:19 45 7±1 1:19 60 9±2 1:12 180 23±4 1:6.2 195 23±3 1:6.2 240 24±3 1:6.0 30 58.4 mM 3a 25 20 15 y = (0.44±0.04)x R² = 0.9802 10 5 0 0 5 10 15 20 Time (min) Figure B.32. Table B.4., Entry 9: Initial rate of the formation of 4aa versus time (min) with 10.9 mM 1e, 218 mM 2a, and 58.4 mM 3a. 281 [4aa] (mM) 300 58.4 mM 3a 250 200 150 100 50 0 0 50 100 150 200 250 300 Time (min) Figure B.33. Table B.4., Entry 9: Full reaction profile for the formation of 4aa over time (min) with 10.9 mM 1e, 218 mM 2a, and 58.4 mM 3a. Table B.12. Table B.4., Entry 9: [4aa] (mM) and selectivity (l:b) of 4aa formed with 10.9 mM 1e, 218 mM 2a, and 58.4 mM 3a. Time (min) [4aa] (mM) Selectivity (l:b) 4 1.5±0.2 1:2.0 8 3.25±0.03 1:2.1 12 4.3±0.3 1:3.8 16 8±3 1:3.9 20 13±7 1:5.2 30 9.9±0.3 1:4.5 40 13±2 1:4.4 50 16±2 1:4.4 60 18±2 1:4.3 90 25.6±0.4 1:4.1 120 29.7±0.1 1:4.1 180 33±3 1:4.0 210 35±4 1:4.0 240 36±4 1:4.0 270 36±5 1:4.2 282 [4aa] (mM) 30 121 mM 3a 25 20 15 y = (1.13±0.04)x 10 R² = 0.9933 5 0 0 2 4 6 8 10 12 Time (min) Figure B.34. Table B.4., Entry 10: Initial rate of the formation of 4aa over time (min) with 10.9 mM 1e, 218 mM 2a, and 121 mM 3a. 300 121 mM 3a 250 200 150 100 50 0 0 50 100 150 200 250 300 Time (min) Figure B.35. Table B.4., Entry 10: Full reaction profile for the formation of 4aa over time (min) with 10.9 mM 1e, 218 mM 2a, and 121 mM 3a. 283 [4aa] (mM) [4aa] (mM) Table B.13. Table B.4., Entry 10: [4aa] (mM) and selectivity (l:b) of 4aa formed with 10.9 mM 1e, 218 mM 2a, and 121 mM 3a. Time (min) [4aa] (mM) Selectivity (l:b) 1 1.0±0.3 1:2.7 2 1.8±0.1 1:3.5 3 3.1±0.3 1:5.3 4 4.0±0.07 1:6.4 5 5.0±0.3 1:7.2 10 12±2 1:7.9 20 23±1 1:8.1 30 32.8±0.8 1:7.8 45 47.1±0.8 1:7.3 60 72±11 1:6.8 90 92±9 1:6.0 120 101±5 1:5.7 160 105±4 1:5.5 255 114±1 1:5.3 30 Entry 3: 242 mM 3a Entry 10: 121 mM 3a 25 Entry 9: 58.4 mM 3a y = (1.59±0.08)x Entry 8: 26.9 mM 3a R² = 0.9845 20 y = (1.13±0.04)x 15 R² = 0.9933 y = (0.44±0.04)x 10 R² = 0.9802 5 y = (0.18±0.01)x R² = 0.9828 0 0 5 10 15 20 25 Time (min) Figure B.36. Table B.13., Entry 3, 8-10: Initial rates of the formation of 4aa versus time (min) with 26.9, 58.4, 121, and 242 mM 3a (all with 10.9 mM 1e, 218 mM 2a). 284 [4aa] (mM) 300 Entry 3: 242 mM 3a Entry 10: 121 mM 3a 250 Entry 9: 58.4 mM 3a Entry 8: 26.9 mM 3a 200 150 100 50 0 0 50 100 150 200 250 300 Time (min) Figure B.37. Rates of formation of [4aa] (mM) with 26.9, 58.4, 121, and 242 mM 3a (all with 10.9 mM 1e, 218 mM 2a). 5 y = 0.0062x(1.0±0.1)4 R² = 0.936 3 2 1 0 0 50 100 150 200 250 300 [3a] (mM) Figure B.38. Plot of Δ[4aa]/Δt (mM/min) versus [3a] (mM). Error bars are present but are not visible. d. Hammett Plot i. Silane Derivatives 285 Δ[4aa]/Δt (mM/min) [4aa] (mM) General Procedure: In a nitrogen-filled glovebox, a stock solution was prepared by weighing out 1e (7.8 mg, 2.7x10-3 M) and dissolving in toluene (5.0 mL) using volumetric glassware. The stock solution of 1e (1.9 mg, 3.3x10-3 mmol, 0.025 equiv, 1.2 mL of stock solution) was distributed into two 1-dram scintillation vials equipped with stir bars using a disposable 1-mL syringe. An additional amount of toluene (1.2 mL), 2a (15 μL, 0.13 mmol, 1.0 equiv), and mesitylene (10 μL, 0.072 mmol) were added to each vial and then sealed with a septum cap. The reactions were brought out of the glovebox, injected with the corresponding amount of silane (3a,c-e, 0.14 mmol, 1.1 equiv), and placed on an aluminum vial block preheated to 80 °C. Throughout the course of the reaction, 20 μL aliquots were removed with a 25-μL syringe and filtered into a GC vial through Celite and diluted with hexanes. The filtrate was analyzed by GC to assess the reaction progress and selectivity. The product concentration was determined by relative integration (by GC) of the product peaks against mesitylene, in accordance with calibration curves. Two trials were run for all experiments. 286 10 Average of Trials 1 & 2 8 6 4 y = (1.75±0.06)x R² = 0.9938 2 0 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Time (min) Figure B.39. Initial rate of the formation of 4ae versus time (min). 60 50 40 30 20 Average of Trials 1 & 2 10 0 0 50 100 150 200 250 300 Time (min) Figure B.40. Full reaction profile for the formation of 4ae over time. Table B.14. [4ae] (mM) and selectivity (l:b) of 4ae formed. Time (min) [4ae] (mM) Selectivity (l:b) 0.17 0.3 ± 0.1 1:0.2 0.33 0.6 ± 0.1 1:0.2 0.5 0.8 ± 0.2 1:0.3 0.67 1.0 ± 0.2 1:0.8 0.83 1.46 ± 0.05 1:1.4 1 1.9 ± 0.2 1:3.0 1.33 4.1 ± 0.5 1:8.4 287 [4ae] (mM) [4ae] (mM) 1.66 6.6 ± 0.6 1:12 2 10 ± 1 1:13 2.5 15 ± 2 1:25 3 16.3 ± 0.4 1:27 3.5 20 ± 4 1:20 5 40 ± 11 1:52 6 53 ± 2 1:53 7 54 ± 2 1:56 9 53 ± 2 1:67 15 51 ± 2 1:62 30 54.1 ± 0.2 1:58 60 51 ± 4 1:58 120 50 ± 2 1:63 198 51.4 ± 0.5 1:67 258 50.3 ± 0.3 1:64 300 52 ± 3 1:69 10 Average of Trials 1 & 2 y = (1.37±0.09)x 8 R² = 0.9585 6 4 2 0 0 1 2 3 4 5 Time (min) 288 [4ad] (mM) Figure B.41. Initial rate of the formation of 4ad versus time (min). 60 50 40 30 20 Average of Trials 1 & 2 10 0 0 50 100 150 200 250 300 350 Time (min) Figure B.42. Full reaction profile for the formation of 4ad over time. Table B.15. [4ad] (mM) and selectivity (l:b) of 4ad formed. Time (min) [4ad] (mM) Selectivity (l:b) 0.17 0.12 ± 0.08 1:0.3 0.33 015 ± 0.04 1:0.2 0.5 0.31 ± 0.07 1:0.4 0.75 0.55 ± 0.09 1:0.6 1 0.6 ± 0.1 1:0.8 1.33 1.0 ± 0.1 1:2.0 1.67 1.7 ± 0.4 1:2.9 2 1.9 ± 0.2 1:4.8 3 4 ± 2 1:4.7 3.5 6 ± 2 1:10.9 4 5.7 ± 0.9 1:12.7 5 7.73 ± 0.06 1:15.0 7 12 ± 1 1:17.8 10 18.955 ± 0.009 1:24.9 15 29 ± 2 1:27.6 30 49 ± 4 1:28.7 60 52 ± 5 1:27.7 120 51 ± 5 1:28.1 180 52.1 ± 0.2 1:27.8 240 53 ± 2 1:27.9 300 53 ± 2 1:28.3 289 [4ad] (mM) 290 10 Average of Trials 1 & 2 8 y = (0.31±0.02)x 6 R² = 0.9839 4 2 0 0 5 10 15 20 25 Time (min) Figure B.43. Initial rate of the formation of 4aa versus time (min). 60 50 40 30 20 Average of Trials 1 & 2 10 0 0 50 100 150 200 250 300 350 Time (min) Figure B.44. Full reaction profile for the formation of 4aa over time. Table B.16. [4aa] (mM) yield and selectivity (l:b) of 4aa formed. Time (min) [4aa] (mM) Selectivity (l:b) 291 [4aa] (mM) [4aa] (mM) 1 0.40 ± 0.04 1:1.3 2 0.93 ± 0.04 1:1.4 3 1.3 ± 0.1 1:1.4 4 1.7 ± 0.1 1:1.6 5 1.939 ± 0.004 1:1.6 7 2.5 ± 0.5 1:1.6 10 3.4 ± 0.2 1:1.8 20 5.73 ± 0.09 1:2.0 30 7.78 ± 0.06 1:2.1 45 11.4 ± 0.2 1:2.2 60 15.9 ± 0.3 1:2.3 80 21 ± 1 1:2.3 100 26.4 ± 0.4 1:2.3 120 33 ± 4 1:2.3 150 36 ± 4 1:2.6 186 40 ± 2 1:2.8 232 38 ± 2 1:2.7 315 41 ± 1 1:2.8 292 10 8 Average of Trials 1 & 2 6 y = (0.099±0.006)x R² = 0.975 4 2 0 0 10 20 30 40 50 Time (min) Figure B.45. Initial rate of the formation of 4ac versus time (min). 60 50 40 30 20 Average of Trials 1 & 2 10 0 0 50 100 150 200 250 300 350 Time (min) Figure B.46. Full reaction profile for the formation of 4ac over time. Table B.17. [4ac] (mM) and selectivity (l:b) of 4ac formed. 293 [4ac] (mM) [4ac] (mM) Time (min) [4ac] (mM) Selectivity (l:b) 2 0.17 ± 0.04 1:2.5 4 0.380 ± 0.008 1:5.5 6 0.45 ± 0.06 1:8.2 8 0.643 ± 0.009 1:7.2 13 0.94 ± 0.05 1:19 20 1.47 ± 0.04 1:19 32.5 2.9 ± 0.1 1:9.6 45 5.09 ± 0.09 1:3.6 62 10 ± 1 1:2.2 80 17.0 ± 0.4 1:3.1 100 23.4 ± 0.9 1:1.8 120 28 ± 3 1:1.7 160 39 ± 5 1:1.6 176 48.2 ± 0.3 1:1.7 210 49 ± 1 1:1.8 260 51 ± 3 1:1.8 315 52 ± 4 1:1.8 10 y = (1.75±0.06)x 4ae (R = 4-CF3) 4ad (R = 3-F) R² = 0.9938 8 4aa (R = H) y= (1.37±0.09)x 4ac (R = 4-CH3) R² = 0.9377 6 y= (0.31±0.02)x 4 R² = 0.9839 2 y = (0.099±0.006)x R² = 0.975 0 0 10 20 30 40 50 Time (min) Figure B.47. Initial rates for the formation of the corresponding [product] (mM) versus time (min). 294 [product] (mM) 60 50 40 30 4ae (R = 4-CF3) 20 4ad (R = 3-F) 4aa (R = H) 10 4ac (R = 4-CH3) 0 0 50 100 150 200 250 300 350 Time (min) Figure B.48. Full reaction profile for the formation of product over time. Table B.18. Corresponding functional group (R), σ value, kobs (mM/min), kX/kH, and log(kX/kH) using 3a,c-e. R σ kobs (mM/min) kX/kH log(kX/kH) 4-CH3 (3c) -0.17 0.099 ± 0.006 0.32 ± 0.03 -0.50 ± 0.03 H (3a) 0 0.31 ± 0.02 1.00 ± 0.07 0.00 ± 0.03 3-F (3d) 0.337 1.37 ± 0.09 4.4 ± 0.4 0.64 ± 0.04 4-CF3 (3e) 0.54 1.75 ± 0.06 7 ± 1 0.87 ± 0.08 2 1.5 4-CF 1 33-F 0.5 H 0 4-CH3 -0.5 y = (1.6±0.2)x R² = 0.9396 -1 -0.3 -0.1 0.1 0.3 0.5 0.7 σ Figure B.49. Hammett Plot: log(kX/kH) versus σ of electronically varied silanes (3a,c-e). Error bars are present but are not visible. 295 log(kX/kH) [product] (mM) ii. Styrene Derivatives General Procedure: In a nitrogen-filled glovebox, a stock solution was prepared by weighing out 1e (7.8 mg, 2.7x10-3 M) and dissolved in toluene (5.0 mL) using volumetric glassware. The stock solution of 1e (1.9 mg, 3.3x10-3 mmol, 0.025 equiv, 1.2 mL of stock solution) was distributed into two 1-dram scintillation vials equipped with stir bars using a disposable 1 mL syringe. An additional amount of toluene (1.2 mL), the corresponding styrene (2a,c,e-g, 0.13 mmol, 1.0 equiv), and mesitylene (10 µL, 0.072 mmol) were added to each vial and then sealed with a septum cap. The reactions were brought out of the glovebox, injected with 3a (0.14 mmol, 1.1 equiv), and placed on an aluminum vial block preheated to 80 °C. Throughout the course of the reaction, 20 μL aliquots were removed with a 25-μL microliter syringe and filtered into a GC vial through Celite and diluted with hexanes. The filtrate was analyzed by GC to assess the reaction progress and selectivity. The product concentration was determined by relative integration (by GC) of the product peaks against mesitylene, in accordance with calibration curves. Two trials were run for all experiments. 296 10 Average of Trials 1 & 2 8 6 y = (0.45±0.02)x R² = 0.9944 4 2 0 0 2 4 6 8 10 12 Time (min) Figure B.50. Initial rate for the formation of 4ca versus time (min). 60 50 40 30 20 Average of Trials 1 & 2 10 0 0 50 100 150 200 250 300 350 Time (min) Figure B.51. Full reaction profile for the formation of 4ca over time. Table B.19. [4ca] (mM) and selectivity (l:b) of 4ca formed. Time (min) [4ca] (mM) Selectivity (l:b) 1 0.44 ± 0.08 1:0.4 2 1.1 ± 0.5 1:0.8 4 1.63 ± 0.01 1:2.5 5 1.9 ± 0.2 1:3.1 7 3.27 ± 0.09 1:3.2 10 4.6 ± 0.6 1:4.5 15 6.5 ± 0.6 1:5.0 20 8.8 ± 0.5 1:5.2 297 [4ca] (mM) [4ca] (mM) 30 11.8 ± 0.6 1:5.2 45 18.15 ± 0.07 1:5.5 60 26 ± 2 1:5.6 80 32 ± 4 1:5.5 100 43 ± 3 1:5.7 120 55 ± 7 1:6.1 162 46.8 ± 0.6 1:6.1 188 48 ± 7 1:6.2 246 48 ± 6 1:6.1 312 45 ± 4 1:6.2 10 Average of Trials 1 & 2 8 y = (0.286±0.008)x 6 R² = 0.9949 4 2 0 0 5 10 15 20 Time (min) Figure B.52. Initial rate of the formation of 4ea versus time (min). 298 [4ea] (mM) 60 50 40 30 20 Average of Trails 1 & 2 10 0 0 50 100 150 200 250 300 350 Time (min) Figure B.53. Full reaction profile for the formation of 4ea over time. Table B.20. [4ea] (mM) and selectivity (l:b) of 4ea formed. Time (min) [4ea] (mM) Selectivity (l:b) 1 0.27 ± 0.02 1:0.4 2 0.46 ± 0.03 1:1.3 3 0.9 ± 0.3 1:1.3 4 1.2 ± 0.1 1:1.8 5 1.1 ± 0.5 1:1.7 7 1.999 ± 0.009 1:2.6 10 2.7 ± 0.4 1:3.0 15 4.5 ± 0.6 1:2.6 20 6 ± 1 1:3.2 30 8 ± 2 1:3.1 45 12 ± 2 1:3.2 60 18 ± 1 1:3.3 80 24 ± 3 1:3.3 100 29 ± 4 1:3.3 120 35 ± 5 1:3.6 162 35 ± 3 1:3.7 188 34 ± 3 1:3.5 246 40 ± 12 1:3.5 312 40 ± 11 1:3.5 299 [4ea] (mM) 10 Average of Trials 1 & 2 8 6 4 y = (0.201±0.004)x R² = 0.9978 2 0 0 5 10 15 20 25 30 35 Time (min) Figure B.54. Initial rate for the formation of 4fa versus time (min). 60 Average of Trials 1 & 2 50 40 30 20 10 0 0 50 100 150 200 250 300 Time (min) Figure B.55. Full reaction profile for the formation of 4fa over time. Table B.21. [4fa] (mM) and selectivity (l:b) of 4fa formed. Time (min) [4fa] (mM) Selectivity (l:b) 1 0.09 ± 0.01 1:0.5 300 [4fa] (mM) [4fa] (mM) 2 0.33 ± 0.07 1:1.2 3 0.54 ± 0.01 1:1.2 4 0.69 ± 0.01 1:1.5 5 0.90 ± 0.06 1:1.4 10 2.010 ± 0.005 1:1.6 20 4.3 ± 0.2 1:1.6 30 5.9 ± 0.1 1:1.5 45 8.7 ± 0.5 1:1.5 60 11.6 ± 0.4 1:1.4 80 16.5 ± 0.7 1:1.4 100 19.4 ± 0.2 1:1.4 125 23.3 ± 0.1 1:1.5 155 30 ± 2 1:1.6 202 29 ± 2 1:1.7 308 26 ± 2 1:1.7 10 Average of Trials 1 & 2 8 6 y = (0.137±0.004)x R² = 0.9931 4 2 0 0 5 10 15 20 25 30 35 Time (min) Figure B.56. Initial rate for the formation of 4ga versus time (min). 301 [4ga] (mM) 60 50 Average of Trials 1 & 2 40 30 20 10 0 0 50 100 150 200 250 300 Time (min) Figure B.57. Full reaction profile for the formation of 4ga over time. Table B.22. [4ga] (mM) and selectivity (l:b) of 4ga formed. Time (min) [4ga] (mM) Selectivity (l:b) 2 0.3 ± 0.2 1:1.0 4 0.3797 ± 0.0004 1:2.4 6 0.65 ± 0.01 1:3.5 8 0.93 ± 0.04 1:3.7 10 1.2 ± 0.1 1:4.0 15 1.8 ± 0.1 1:4.6 20 2.9 ± 0.2 1:4.8 30 4.3 ± 0.9 1:5.4 45 6.3 ± 0.9 1:5.7 60 8 ± 2 1:5.8 90 13 ± 3 1:5.6 120 18 ± 3 1:5.6 150 22 ± 5 1:5.5 180 27.2 ± 0.1 1:5.7 235 29 ± 2 1:6.1 320 33 ± 7 1:6.8 302 [4ga] (mM) 10 y= (0.31±0.02)x y = (0.201±0.004)x R² = 0.9839 R² = 0.9964 8 y = (0.286±0.008)x y = (0.137±0.004)x R² = 0.9949 R² = 0.9931 6 y = (0.45±0.02)x R² = 0.9944 4 4ca (R = OCH3) 4ea (R = CH3) 2 4aa (R = H) 4fa (R = F) 4ga (R = CF3) 0 0 10 20 30 Time (min) Figure B.58. Initial rate data for the formation of the corresponding [product] (mM) versus time (min). 60 50 40 30 20 4ca (R = OCH3) 4ea (R = CH3) 10 4aa (R = H) 4fa (R = F) 4ga (R = CF3) 0 0 50 100 150 200 250 300 Time (min) Figure B.59. Full reaction profile for the formation of product over time. Table B.23. Functional group (R), σ value, kobs (mM/min), kX/kH, and log(kX/kH) using 2a,c-g. R ρ kobs (mM/min) kX/kH log(kX/kH) 4-OCH3 (2c) -0.268 0.45 ± 0.02 1.44 ± 0.04 0.16 ± 0.01 4-CH3 (2d) -0.17 0.285 ± 0.008 0.92 ± 0.02 -0.0382 ± 0.009 H (2a) 0 0.31 ± 0.02 1.00 ± 0.03 0.00 ± 0.01 303 [product] (mM) [product] (mM) 4-F (2e) 0.062 0.208 ± 0.004 0.64 ± 0.01 -0.191 ± 0.009 4-CF3 (2f) 0.54 0.137 ± 0.004 0.441 ± 0.009 -0.356 ± 0.009 2.0 y = (-0.6±0.2)x R² = 0.7662 1.0 4-OCH3 4-CH3 H 4-F 0.0 4-CF3 -1.0 -0.3 -0.1 0.1 0.3 0.5 0.7 σ Figure B.60. Hammett Plot log(kX/kH) versus σ of electronically varied styrenes (2a,c-g). Error bars are present but are not visible. B.1.7. Other Mechanistic Reactions a. Hydrosilylation in the Presence of 1,1-Diphenylethylene (DPE) General Procedure: In a nitrogen-filled glovebox, a stock solution was prepared by weighing out 1e (38 mg, 0.066 mmol, 0.033 M) and toluene (2.0 mL) was added. The stock solution of 1e (7.6 mg, 0.013 mmol, 0.025 equiv, 0.40 mL of stock solution) was added to a 1- dram scintillation vial equipped with a stir bar using a disposable 1-mL syringe. An additional stock solution was prepared by weighing out durene (54 mg, 0.40 mmol, 0.13 M) and dissolved in toluene (3.0 mL). The stock solution of durene (11 mg, 0.082 mmol, 0.60 mL of stock solution) was added to the 1-dram scintillation vial containing 1e using a disposable 1-mL syringe. An additional amount of toluene (0.20 mL) and 2a (30 μL, 0.26 mmol, 1.0 equiv) were added to the vial, which was then sealed with a septum cap, and the vials were brought out of the glovebox. DPE was added via 100-μL syringe to the reactions (0 or 51 μL, 0 or 0.29 mmol, 0 or 1.1 equiv), 304 log(kX/kH) followed by 3a (54 μL, 0.29 mmol, 1.1 equiv), which was added via a 100-μL syringe. The reaction was then placed on an aluminum vial block preheated to 80 °C. Throughout the course of the reaction, 20-μL aliquots were removed with a 25-μL syringe and filtered into a GC vial through Celite and diluted with hexanes. The filtrate was analyzed by GC to assess the reaction progress and selectivity. The product concentration was determined by relative integration (by GC) of the product peaks against mesitylene, in accordance with calibration curves. Two trials were run for both experiments and in parallel. 300 250 200 150 100 without DPE with DPE 50 0 0 50 100 150 200 250 300 Time (min) Figure B.61. Full reaction profile for the hydrosilylation of 2a and 3a catalyzed by 1e with DPE (pink squares) and without DPE (blue circles) for the formation of 4aa versus time (min). Table B.24. Concentration of 4aa (mM) and selectivity (l:b) over time for the hydrosilylation of 2a and 3a catalyzed by 1e without and with DPE. Without DPE With DPE Time (min) [4aa] (mM) Selectivity (l:b) [4aa] (mM) Selectivity (l:b) 1 0.7 ± 0.6 1:2.3 1.19 ± 0.02 1:2.0 2 2.518 ± 0.007 1:4.3 2.7 ± 0.1 1:4.0 3 4.2 ± 0.3 1:5.4 1 ± 2 1:4.3 4 5.7 ± 0.1 1:7.6 5.8 ± 0.5 1:6.4 5 7.0 ± 0.9 1:8.4 7.6 ± 0.1 1:6.7 10 15 ± 1 1:9.2 16.41 ± 0.05 1:8.0 15 25.3 ± 0.4 1:9.9 -- -- 21 37.4 ± 0.7 1:9.1 35 ± 3 1:8.0 30 50 ± 3 1:8.4 49.8 ± 0.4 1:8.6 305 [4aa] (mM) 40 83 ± 5 1:7.6 65 ± 9 1:7.7 60 100 ± 7 1:7.1 -- -- 80 143 ± 4 1:6.9 137 ± 19 1:7.2 100 169.97 ± 0.03 1:7.4 164 ± 9 1:7.5 120 203.46 ± 0.04 1:7.9 194 ± 18 1:8.1 150 194.46 ± 0.03 1:8.0 224 ± 30 1:9.2 180 181.956 ± 0.003 1:8.1 -- -- 240 185.12 ± 0.04 1:8.9 192 ± 4 1:2.0 b. Reaction of 1e, Diphenylsilane (3a), and a 1,6-diene (2s) General Procedure: In a nitrogen-filled glovebox, 1e (25 mg, 0.044 mmol, 0.05 equiv) was directly weighed out into a 4-dram scintillation vial equipped with a stir bar and toluene (4.0 mL, 0.22 M) was added using a disposable 5-mL syringe. The vial was capped with a septum cap, brought out of the glovebox, injected with 2s (0.16 mL, 0.87 mmol, 1.0 equiv) and 3a (0.18 mL, 0.96 mmol, 1.1 equiv), and placed in an oil bath pre-heated to 100 °C. After 4 h, the reaction was quenched by freezing it in liquid N2, and then it was thawed and concentrated to obtain the crude product. The crude reaction was treated with hexanes (5.0 mL), filtered through silica (eluting with 5:95 benzene/hexanes) to remove remaining Ni catalyst, concentrated, and analyzed by 1H NMR. The crude product was purified by column chromatography (gradient 0-5% benzene/hexanes) to isolate and identify each product formed in the reaction. 1H NMR spectra match previously reported values.6,287 306 Figure B.62. 1H NMR spectrum for the crude reaction mixture from 1e-catalyzed hydrosilylation of 2s and 3a in CDCl3 at 25 °C. The major product of the reaction of 2s and 3a is the linear hydrosilylation product 4sa. Unreacted 2s, partially hydrogenated 2s (5), and hydrosilylated styrene (4aa) were also found in the crude reaction mixture. No evidence of radical cyclization products 4sa’, 6a, or 7aa were observed. 307 Further confirmation of the absence of the cyclized product (6a) in the hydrosilylation of 2s with 3a was obtained by independently synthesizing and isolating 6a via a Wittig reaction according to a literature procedure6 for comparison. It was difficult to discern the absence of 6a by 1H NMR due to possible overlapping peaks; therefore, GC analysis of both the crude reaction and independently synthesized 6a confirmed the absence of 6a in the crude, 1e-catalyzed reaction between 2s and 3a. Figure B.63. 1H NMR spectrum for the independently synthesized 6a (top), and the crude reaction mixture from 1e-catalyzed hydrosilylation of 2s and 3a (bottom) in CDCl3 at 25 °C. 308 Figure B.64. GC-MS trace of the crude reaction mixture from 1e-catalyzed hydrosilylation of 2s and 3a (purple trace) and of 6a synthesized independently (blue trace). c. Hydrosilylation of 3a with cyclized alkene (6a) General Procedure: In a nitrogen-filled glovebox, 1e (14 mg, 0.025 mmol, 0.050 equiv) was directly weighed out into a 1-dram scintillation vial equipped with a stir bar and toluene (2.3 mL, 0.22 M) was added using a disposable 5-mL syringe. The vial was capped with a septum cap, brought out of the glovebox, injected with 6a (88 µL, 0.50 mmol, 1.0 equiv) and 3a (100 µL, 0.55 mmol, 1.1 equiv), and placed in a pre-heated aluminum vial block to 100 °C. After 4 h, the reaction was quenched by freezing it in liquid N2, and then it was thawed and concentrated to obtain the crude product. The crude reaction was treated with hexanes (1.0 mL), filtered through silica (eluting with 5:95 benzene/hexanes) to remove remaining Ni catalyst, concentrated, and analyzed by 1H NMR and GC-MS. No evidence of the hydrosilylated product (7aa) of 6a with 3a was observed by 1H NMR or GC-MS. 309 Figure B.65. 1H NMR spectrum for the crude reaction mixture from 1e-catalyzed hydrosilylation of 6a and 3a in CDCl3 at 25 °C. B.1.13. NMR and IR Spectra a. Deuterated Diphenylsilane (3a-d2) 310 Figure B.66. 1H NMR spectrum of diphenylsilane-d2 (3a-d2) recorded in CDCl3 at 298 K. 311 APPENDIX C SUPPLEMENTARY CONTENT FOR CHAPTER IV Experimental Details C.1.1. Materials and Methods All syntheses and manipulations were carried out under nitrogen using standard Schlenk (vacuum 10-2 mbar) techniques or in a nitrogen-filled glovebox unless otherwise indicated. All reagents and solvents were used after drying and stored under nitrogen, unless otherwise indicated. Tetrahydrofuran (THF; Fisher Chemical; HPLC grade, unstabilized), hexanes (Fisher Chemical; HPLC grade), diethyl ether (B&J Brand; HPLC grade, unstabilized) and acetonitrile (Fisher Chemical; HPLC grade) were dispensed under nitrogen from an LC Technology SP-1 solvent system. Benzene (ACS grade) and pentane (HPLC grade) were refluxed overnight with CaH2 and distilled under nitrogen before use. The dried solvents were thereafter stored on activated 4Å molecular sieves under nitrogen. CD3CN, C6D6 and CDCl3 were purchased from Cambridge Isotope Laboratories, degassed by freeze-pump-thaw, and thereafter stored on activated 4Å molecular sieves under nitrogen. All stock solutions were prepared by mass and were dispensed into the reaction vessel by difference from syringe, as detailed in the procedure for each experiment. The following reagents were used from commercial sources without further purification: lithium aluminum deuteride (Aldrich Chemical), styrene-d8 (2a-d8; Fisher Scientific), 4- methoxystyrene (2c; Alfa Aesar), 4-methylstyrene (2e; TCI), 4-fluorostyrene (2f; Matrix), 2- methylstyrene (2h; TCI), durene (Eastman Chemical Company), and 1,3,5-trimethoxybenzene (TCI). 1l, 1m, 1n were synthesized via reported procedures.126 C.1.2. General Experimental Nuclear magnetic resonance (NMR) spectra were collected at room temperature (298 K) unless otherwise stated on a Bruker AV-III HD 600 NMR (600.13 MHz for 1H; 150.90 MHz for 13C; 564.69 MHz for 19F; 119.23 MHz for 29Si; 92.12 MHz for 2H), Bruker Avance-III HD 500 NMR (499.90 MHz for 1H; 126 MHz for 13C; 471 MHz for 19F; 99 MHz for 29Si), or Varian Inova 312 500 NMR (499.90 MHz for 1H; 126 MHz for 13C; 471 MHz for 19F; 99 MHz for 29Si). 1H and 13C spectra were referenced to the residual solvent peak (CDCl : 1H δ = 7.26 ppm, 133 C δ = 77.16 ppm; C D : 16 6 H δ = 7.16 ppm, 13C δ = 128.06 ppm, CD 1 133CN: H δ = 1.94 ppm, C δ = 1.32 ppm (NCCD3)). Chemical shifts for 1H, 13C, and 29Si NMR spectra are reported in parts per million (ppm, δ) relative to tetramethylsilane at 0.00 ppm. Peaks are characterized as follows: s (singlet), d (doublet), t (triplet), q (quartet), pent (pentet), hept (heptet), m (multiplet), qd (quartet of doublets), br (broad), app (apparent), and/or ms (multiple signals). Coupling constants, J, are reported in Hz. 1JH–Si coupling constants were determined, when possible, using the 29Si satellites in the 1H NMR spectrum. Infrared (IR) spectroscopy for air-stable organic compounds was performed on an Agilent Nicolet 6700 FT-IR using the ATR sampling technique. IR spectra for air-sensitive nickel complexes were recorded as self-supported pellets diluted with KBr using a Bruker Alpha II FT- IR spectrometer that is housed in a nitrogen-filled glovebox. All bands are reported in wavenumbers (cm-1) and are described as broad (br), strong (s), medium (m), and weak (w). C.1.3. Synthesis of Nickel Complexes (IMes)Ni(µ-H–SiPh2)2Ni(IMes) (1g). To a 10-mL round bottom flask equipped with a magnetic stir bar was added 1e (0.10 g, 0.18 mmol, 1.0 equiv) and H2SiPh2 (0.16 mL, 0.88 mmol, 5.0 equiv) in THF (5.0 mL). The reaction was stirred at room temperature overnight and then concentrated under reduced pressure to give a dark red solid. The product was purified by solvating the solid in minimal amounts of THF (2.0 mL) and precipitation with hexanes (5.0 mL). The product was collected by vacuum filtration to yield 1g as an orange powder (0.064 g, 0.059 mmol, 67% yield). A single crystal for analysis was grown via hexanes/THF slow vapor diffusion (see section 12 below). 313 1H NMR (500 MHz, C6D6, 298 K): 7.32 (d, J = 7.4 Hz, 12H), 7.19 (t, J = 7.4 Hz, 8H), 6.57 (s, 8H), 6.05 (s, 4H), 2.27 (s, 12H), 1.62 (s, 24H), -2.22 (s, 2H). 13C{1H} NMR (126 MHz, C6D6, 298 K): δ 195.9, 146.0, 137.0, 136.9, 136.9, 136.0, 129.3, 126.9, 126.4, 121.8, 21.3, 17.8. 29Si NMR (119 MHz, C6D6, 298 K): δ 107.76 (s). IR (ATR, neat) ν: 3133-2848 (w), 1588 (w), 1490 (w), 1220 (w), 688 (s). ASAP/HRMS (m/z): [M+] calculated for C66H70N4Ni2Si2 1090.3846, found 1090.3821. (4-methoxystyrene)2Ni(IMes) (1h) To a 2-dram scintillation vial equipped with a magnetic stir bar was added Ni(cod)2 (0.073 g, 0.26 mmol, 1.0 equiv), 4-methoxystyrene (0.28 mL, 2.1 mmol, 8.0 equiv), and THF (4.0 mL). This red solution was stirred for 15 min at room temperature. In a 2-dram scintillation vial was added IMes (0.080 g, 0.26 mmol, 1.0 equiv) and THF (4.0 mL). This solution was added dropwise to the Ni(cod)2 and 4-methoxystyrene mixture to afford a red solution. This reaction was stirred for 2 h and then was concentrated under reduced pressure to give an orange solid. The crude product was dissolved in minimal amounts of THF (3.0 mL) and filtered through Celite. The filtrate was concentrated under reduced pressure, solvated in minimal THF (3.0 mL), and then hexanes (10 mL) was added to precipitate 1h out of solution. The product was collected via vacuum filtration and dried under reduced pressure to yield 1h as a yellow powder (0.069 g, 0.11 mmol, 42% yield). 1H NMR (500 MHz, C6D6, 298 K): δ 6.80 (s, 2H), 6.75 (s, 2H), 6.68 (d, J = 8.4 Hz, 4H), 6.45 (d, J = 8.4 Hz, 4H), 6.28 (s, 2H), 3.43 (s, 6H), 3.37 (dd, J = 12.4, 9.6 Hz, 2H), 2.74-2.70 (ms, 4H), 2.20 (s, 6H), 2.11 (s, 6H), 2.02 (s, 6H). 13C{1H} NMR (126 MHz, C6D6, 298 K): δ 203.4, 156.8, 140.0, 138.5, 137.9, 136.3, 135.6, 129.6, 129.5, 125.1, 122.7, 113.6, 72.7, 54.8, 48.3, 21.1, 18.5, 18.3 . IR (FT, KBr pellet) ν: 3163-2833 (w), 1508 (s), 1305 (s), 1039 (s), 831 (s). 314 ASAP/HRMS (m/z): [M+] calculated for C39H44N2NiO2 630.2756, found 630.2762. (4-fluorostyrene)2Ni(IMes) (1i) To a 4-dram scintillation vial equipped with a magnetic stir bar was added Ni(cod)2 (0.10 g, 0.36 mmol, 1.0 equiv), 4-fluorostyrene (0.30 mL, 2.7 mmol, 6.9 equiv), and THF (5.0 mL). This red solution was stirred for 30 s at room temperature. In a 2-dram scintillation vial was added IMes (0.11 g, 0.36 mmol, 1.0 equiv) and THF (5.0 mL). This solution was immediately added dropwise to the Ni(cod)2 and 4-fluorostyrene mixture to afford a red solution. This reaction was stirred for 2 h and then was concentrated under reduced pressure to give an orange solid. The crude product was dissolved in a minimal amount of THF (3.0 mL) and filtered through Celite. The filtrate was concentrated under reduced pressure. The crude solid was solvated in minimal THF (1.0 mL), hexanes (3.0 mL) was added, and the reaction was placed in the freezer at -30 °C to crystallize overnight. The product was collected by decanting the liquid away from the solid, which was then dried under vacuum to yield 1i as orange crystals (0.053 g, 0.087 mmol, 24% yield). 1H NMR (500 MHz, C6D6, 298 K): δ 6.73-6.70 (ms, 8H), 6.27 (s, 2H), 6.22 (dd, J = 8.66 Hz, 5.68 Hz, 4H), 3.10 (dd, J = 12.5 Hz, 9.5 Hz, 2H), 2.67 (dd, J = 9.5 Hz, 2.2 Hz, 2H), 2.64 (dd, J = 12.5 Hz, 2.2 Hz, 2H) 2.12 (s, 6H), 2.06 (s, 6H), 1.96 (s, 6H) 13C{1H} NMR (126 MHz, C6D6, 298 K): δ 202.0, 161.5 (d, J = 240 Hz), 143.2 (d, J = 2.8 Hz), 138.7, 137.7, 136.2, 135.6, 129.5, 125.2 (d, J = 7.2 Hz), 122.9, 114.5 (d, J = 20.7 Hz), 71.5, 49.0, 21.0, 18.4, 18.2. 19F NMR (471 MHz, C6D6, 298 K): δ -121.17 (m). IR (FT, KBr pellet) ν: 3140-2857 (w), 1505 (s), 1321 (s), 831 (s), 694 (s). ASAP/HRMS (m/z): [M+] calculated for C37H38F2N2Ni 606.2357, found 606.2361. 315 [4-(trifluoromethyl)styrene]2Ni(IMes) (1j) To a 4-dram scintillation vial equipped with a magnetic stir bar was added Ni(cod)2 (0.12 g, 0.45 mmol, 1.0 equiv), 4-(trifluoromethyl)styrene (0.40 mL, 2.7 mmol, 6.0 equiv), and THF (5.0 mL) to afford a red solution. A solution of IMes (0.14 g, 0.45 mmol, 1.0 equiv) and THF (5.0 mL) was immediately added to the Ni(cod)2 and 4- (trifluoromethyl)styrene mixture to afford a red solution. This reaction was stirred for 2 h and then was concentrated under reduced pressure to give an orange solid. The crude product was dissolved in a minimal amount of THF (3.0 mL) and filtered through Celite. The filtrate was concentrated under reduced pressure. The crude solid was solvated in minimal THF (1.0 mL), hexanes (3.0 mL) was added, and the reaction was placed in the freezer at -30 °C to crystallize overnight. The product was collected by decanting the liquid away from the solid, which was dried under reduced pressure to yield 1j as vibrant, orange crystals (0.12 g, 0.17 mmol, 37% yield). 1H NMR (600 MHz, C6D6, 298 K): δ 7.27 (d, J = 8.1 Hz, 4H), 6.71 (s, 2H), 6.67 (s, 2H), 6.24 (d, J = 8.1 Hz, 4H), 6.22 (s, 2H), 2.98 (dd, J = 12.5, 9.4 Hz, 2H), 2.70 (dd, J = 9.4, 2.4 Hz, 2H), 2.68 (dd, J = 12.5, 2.4 Hz, 2H), 2.15 (s, 6H), 2.00 (s, 6H), 1.89 (s, 6H). 13C{1H} NMR (151 MHz, C6D6, 298 K): δ 200.2, 151.0, 139.0, 137.4, 136.0, 135.5, 129.6, 128.3, 126.0 (q, J = 271.0 Hz), 125.1 (q, J = 31.8 Hz), 124.8 (q, J = 3.8 Hz), 124.0, 123.2, 71.1, 50.3, 20.9, 18.3, 18.1. 19F NMR (471 MHz, C6D6, 298 K): δ -61.38 (s). IR (FT, KBr pellet) ν: 3142-2860 (w), 1608 (s), 1321 (s), 840 (s), 693 (s). ASAP/HRMS (m/z): [M+] calculated for C39H38F6N2Ni 706.2293, found 706.2287. 316 (styrene)2Ni(ITMe) (1k) To a 100-mL round bottom flask equipped with a magnetic stir bar was added Ni(cod)2 (1.2 g, 4.3 mmol, 1.0 equiv), styrene (3.9 mL, 34 mmol, 7.9 equiv), and THF (40 mL). This red solution was stirred for 15 min at room temperature. In a 4-dram scintillation vial was added ITMe (0.54 g, 4.3 mmol, 1.0 equiv) and THF (10 mL). This solution was added dropwise to the Ni(cod)2 and styrene mixture to afford a red solution. This reaction was stirred for 2 h and then was concentrated under reduced pressure. The crude product was dissolved in a minimal amount of THF (5.0 mL) and filtered through Celite. The filtrate was concentrated under reduced pressure to give a dark orange solid. The crude solid was solvated in minimal THF (3.0 mL), hexanes (10 mL) was added, and the reaction was placed in the freezer at -30 °C to crystallize overnight. The product was collected by decanting the liquid away from the solid, which was then dried under vacuum to yield 1k as orange crystals (0.70 g, 1.8 mmol, 42% yield). Two rotamers were isolated as 1k, the major rotamer is labelled as A and the minor rotamer is labelled as B. 1H NMR (600 MHz, C6D6, 298 K): δ 7.02 (t, J = 7.4 Hz, 11H, A and B), 6.96-6.87 (ms, 18H, A and B), 4.21 (m, 6H, A and B), 3.37 (dd, J = 12.8, 2.9 Hz, 3H, B), 3.11 (dd, J = 12.5, 2.6 Hz, 4H, A), 3.03 (dd, J = 9.0, 2.4 Hz, 4H, A), 2.98 (s, 3H, B), 2.73 (dd, J = 9.2, 2.9 Hz, 3H, B), 2.51 (s, 12H, A), 1.92 (s, 3H, B), 1.46 (s, 3H, B), 1.41 (s, 12H, A), 1.36 (s, 3H, B) 13C{1H} NMR (151 MHz, C6D6, 298 K): δ 197.5, 197.4, 147.1, 146.9, 125.21, 125.15, 125.0, 124.3, 123.8, 122.93, 122.89, 64.6, 64.2, 46.0, 45.6, 34.1, 33.2, 31.8, 8.7, 8.65, 8.55 C.1.4. Monitoring Hydrosilylation by 1H NMR a. Hydrosilylation of Styrene (2a) and Diphenylsilane (3a) 317 In a nitrogen-filled glovebox, 1e (7.5 mg, 0.013 mmol, 0.10 equiv) was added to a J-Young NMR tube and solvated in C7D8 (0.60 mL, 0.22 M), which was added using a disposable 1-mL syringe. To this solution was added 2a (17 μL, 0.14 mmol, 1.0 equiv) and 3a (27 μL, 0.15 mmol, 1.1 equiv) using a 50-μL syringe and mesitylene (3.5 μL, 0.025 mmol) using a 10-μL syringe. The NMR tube was sealed, brought out of the glovebox, and placed into the NMR (Bruker AV-III HD 600), which had been preheated to 75 °C. Reaction progress was monitored by 1H NMR over time. Quantitative analysis of the formation of 4aa was determined by relative integrations between 4aa (the doublet at 1.45 ppm, 3H) to the integration of the internal standard, mesitylene (singlet at 6.70 ppm, 3H). Figure C.1. 1H NMR-monitored reaction of 2a and 3a catalyzed by 1e over time in C7D8 taken at 75° C. 318 250 200 150 100 50 0 0 100 200 300 400 Time (min) Figure C.2. Kinetic profile of [4aa] (mM) versus time (min). Table C.1. Integrations of mesitylene and 4aa and the calculated [4aa] (mM) over time. ʃmesitylene ʃ4aa Time (min) [4aa] (mM) (6.70 ppm, 3H) (1.45 ppm, 3H) 5 1269.87 140.26 4.63 10 1175.73 174.36 6.22 15 1240.35 259.87 8.79 20 1240.26 373.87 12.64 25 1245.43 489.30 16.47 30 1270.37 605.01 19.97 35 1291.56 734.96 23.86 40 1339.31 887.73 27.79 45 1371.20 1033.00 31.59 50 1371.20 1033.00 31.59 60 1444.96 1359.04 39.44 70 1508.46 1688.50 46.94 80 1559.58 2025.13 54.45 90 1613.14 2540.56 66.04 105 1675.27 3093.50 77.43 120 1711.59 3624.94 88.81 150 1777.13 4970.51 117.29 165 1793.33 5637.69 131.83 180 1835.30 6373.91 145.63 200 1831.09 7033.36 161.07 220 1848.63 7718.53 175.08 319 [4aa] (mM) 240 1853.14 8371.87 189.44 260 1844.10 9002.50 204.71 280 1859.25 9717.16 219.16 300 1907.43 10173.60 223.66 320 1827.85 10149.70 232.85 b. Hydrosilylation of 4-Methoxystyrene (2c) and Diphenylsilane (3a) In a nitrogen-filled glovebox, 1e (7.5 mg, 0.013 mmol, 0.10 equiv) was added to a J-Young NMR tube and solvated in C7D8 (0.60 mL, 0.22 M), which was added using a disposable 1-mL syringe. To this solution was added 2c (18 μL, 0.13 mmol, 1.0 equiv) and 3a (27 μL, 0.14 mmol, 11 equiv) using a 50-μL syringe and mesitylene (3.5 μL, 0.025 mmol) using a 10-μL syringe. The NMR tube was sealed, brought out of the glovebox, and placed into the NMR (Bruker AV-III HD 600), which had been preheated to 75 °C. Reaction progress was monitored by 1H NMR over time. Quantitative analysis of the formation of 4ca was not possible due to overlap of the product peaks with the hydrosilylated styrene (4aa), which formed from the pre-coordinated styrene on 1e reacting with 3a. Peaks corresponding to (IMes)Ni(styrene)(4-methoxystyrene) (1e/h) were identified by reacting 1e (1 equiv) with 2c (1 equiv). See section B.1.7. for more information. 320 Figure C.3. 1H NMR monitored reaction of 2c and 3a catalyzed by 1e over time in C7D8 taken at 75 °C. C.1.5. Styrene Ligand Exchange and Equilibrium Experiments a. Reaction of 1e with Styrene Derivatives In a nitrogen-filled glovebox, 1e (see Table 4) was weighed out directly into a J-Young NMR tube and solvated in C7D8 (0.60 mL, 0.22 M) using a disposable 1-mL syringe. To this solution was added the corresponding styrene derivative and mesitylene (3.0 μL, 0.022 mmol) using a 25-μL syringe. The NMR tube was sealed, removed from the glovebox, and placed in a pre-heated oil bath at 75 °C for 4 h. The reaction was removed from the heat and cooled to room temperature. The resulting reaction mixture was analyzed by 1H and 19F NMR. Quantitative 321 analysis by 1H NMR was determined by the relative integrations of the newly formed products, starting materials, and the internal standard, mesitylene. Peaks corresponding to (IMes)Ni(styrene)(4-X-styrene) (1e/h, 1e/i, and 1e/j) complexes were found by reacting 1e (1.0 equiv) with 1h-j (1.0 equiv) in a comproportionation reaction. See section 8b for more information. Table C.2. Amount of 1e and styrene derivatives (2c,f,g) added to the reaction. Experiment # Reagent Equiv mmol Amount added 1e 1.0 0.013 7.5 mg 1 4-OCH3-styrene (2c) 2.0 0.026 3.50 µL 1e 1.0 0.015 7.5 mg 2 4-F-styrene (2f) 1.8 0.027 3.25 µL 1e 1.0 0.013 7.5 mg 3 4-CF3-styrene (2g) 2.1 0.027 4.0 µL Ligand Exchange Experiment #1: 322 Figure C.5. 1H NMR (500 MHz, 298 K) spectrum of the reaction of 1e and 4-methoxystyrene (2c) after heating in C7D8 taken at 25 °C. Table C.3. Integration of labeled peaks in the 1H NMR spectrum and normalized integrations (integration/#H) of each species in solution. Compound Chemical Shift (ppm) Integration # of protons Normalized integrations 1e 6.37 1.00 4 0.25 4-methoxystyrene (2c) 5.51 0.83 1 0.83 Styrene (2a) 5.57 0.50 1 0.50 1h 3.43 0.56 6 0.093 1e/h 3.41 0.82 3 0.27 Ligand Exchange Experiment #2: 323 Figure C.6. 1H NMR (500 MHz, 298 K) spectrum of the reaction of 1e and 4-fluorostyrene (2f) after heating in C7D8 taken at 25 °C. 324 Figure C.7. 19F NMR (471 MHz, 298 K) spectrum of the reaction of 1e and 4-fluorostyrene (2f) after heating in C7D8 taken at 25 °C. Table C.4. Integration of labeled peaks in the 1H NMR spectrum and normalized integrations (integration/#H) of each species in solution. Compound Chemical Shift (ppm) Integration # of protons Normalized integrations 1e 3.19 0.40 2 0.20 4-fluorostyrene (2f) 5.03 0.51 1 0.51 Styrene (2a) 5.09 0.65 1 0.65 1i 3.02 0.43 2 0.22 1e/i 3.11 0.77 2 0.39 325 Ligand Exchange Experiment #3: Figure C.8. 1H NMR (500 MHz, 298 K) spectrum of the reaction of 1e and 4- (trifluoromethyl)styrene (2g) after heating in C7D8 taken at 25 °C. 326 Figure C.9. 19F NMR (471 MHz, 298 K) spectrum of the reaction of 1e and 4- (trifluoromethyl)styrene (2g) after heating in C7D8 taken at 25 °C. Table C.5. Integration of labeled peaks in the 1H NMR spectrum and normalized integrations (integration/#H) of each species in solution. Compound Chemical Shift Integration # of protons Normalized (ppm) integration 1e 3.19 0.11 2 0.055 4-(Trifluoromethyl)styrene (2g) 5.51 0.40 1 0.40 Styrene (2a) 5.61 1.01 1 1.0 1j 2.92 0.72 2 0.36 1e/j 3.03 0.26 1 0.26 327 Calculation of equilibrium constants: Because we can observe the presence of complex 1e, the intermediate complex A, the product complex B, 4-X-vinylarene, and styrene, the reaction was balanced in the following manner to include each component observed in solution: Therefore, we can use this balanced equation to write an equilibrium expression that describes this reaction: [𝐀][𝐁][𝟐𝐚]3 𝐾eq = [𝟐#]3[𝟏𝐞]2 Using this equilibrium expression, we can calculate the Keq for each reaction and further calculate the log(KX/KH) values (Table S8). Table C.6. Corresponding Hammett parameters (σ), Keq, KX/KH, and log(KX/KH) for the reactions of 2c,f,g with 1e. X σ Keq Keq(X)/Keq(H) log(Keq(X)/Keq(H)) CF3 0.54 498 498 2.70 F 0.062 4.28 4.28 0.632 H 0 - 1 0 OCH3 -0.268 0.0892 0.0892 -1.05 3 y = (4.8±0.4)x R² = 0.9797 4-CF3 2 1 0 4-F H -1 4-OCH3 -2 -0.4 -0.2 0 0.2 0.4 0.6 σ Figure C.10. Hammett Plot of the log(Keq(X)/Keq(H)) versus σ for the ligand exchange experiments with 1e. 328 log(Keq(X)/Keq(H)) b. Reaction of 1e with 1h-j In a nitrogen-glovebox, the (IMes)Ni(4-X-vinylarene)2 complex (1h-j, 0.0066 mmol, 1.0 equiv) was weighed out directly into a J-Young NMR tube and solvated in C7D8 (0.45 mL), which was added using a disposable 1-mL syringe. A stock solution of 1e (25 mg, 0.044 mmol) in toluene (1.0 mL) was prepared in a volumetric flask. This stock solution (0.15 mL, 3.8 mg, 0.0066 mmol, 1.0 equiv) was distributed using a disposable 1-mL syringe into the NMR tube containing the (IMes)Ni(4-X-vinylarene)2 complex. The internal standard, mesitylene (3.5 μL, 0.025 mmol), was added using a 10-μL syringe. The J-Young NMR tube was sealed, removed from the glovebox, and placed in a pre-heated oil bath at 75 °C for 4 h. The reaction was removed from the heat and cooled to room temperature. The resulting reaction mixture was analyzed by 1H and 19F NMR. The corresponding amounts of each Ni complex were used are seen in Table S9. Table C.7. Corresponding amounts of 1h-1j used for each experiment. (IMes)Ni(4-X-vinylarene)2 Amount (mg) Amount (mmol) (IMes)Ni(4-OCH3-styrene)2 (1h) 4.2 0.0066 (IMes)Ni(4-F-styrene)2 (1i) 4.0 0.0066 (IMes)Ni(4-CF3-styrene)2 (1j) 4.7 0.0066 329 Figure C.11. From top to bottom are the 1H NMR spectra of 1e, the reaction of 1e and 1h to form 1e/h, and 1h, respectively, in C7D8 taken at 25 °C. 330 Figure C.12. From top to bottom are the 1H NMR spectra of 1e, the reaction of 1e and 1i to form 1e/i, and 1i, respectively, in C7D8 taken at 25 °C. 331 Figure C.13. From top to bottom are the 19F NMR spectra of the reaction of 1e and 1i to form 1e/i, and of 1i, respectively, in C7D8 taken at 25 °C. 332 Figure C.14. From top to bottom are the 1H NMR spectra of 1e, the reaction of 1e and 1j to form 1e/j, and or 1j, respectively, in C7D8 taken at 25 °C. 333 Figure C.15. From top to bottom are the 19F NMR spectra of the reaction of 1e and 1j to form 1e/j, and 1j respectively, in C7D8 taken at 25 °C. C.1.6. Kinetic Experiments a. NHC Ligand Effects 334 General Procedure: In a nitrogen-filled glovebox, a stock solution was prepared by weighing out the corresponding Ni catalyst (1e, 1k-1o) and dissolving in toluene using volumetric glassware. The stock solution of the Ni catalyst (1e, 1k-1o, 1.3x10-2 mmol, 0.005 equiv) was distributed into two 1-dram scintillation vials equipped with stir bars using a disposable 1-mL syringe. A separate stock solution of the internal standard, durene, and 2a (30 µL, 0.26 mmol, 1.0 equiv) were prepared in toluene using volumetric glassware and distributed into each 1-dram scintillation vial to obtain a total volume of 1.2 mL. The vials were sealed with a septum cap and brought out of the glovebox, injected with 3a (54 µL, 0.29 mmol, 1.1 equiv), and placed on an aluminum vial block preheated to 80 °C. Throughout the course of the reaction, 20 μL aliquots were removed with a 25-μL syringe and filtered into a GC vial through Celite and diluted with hexanes. The filtrate was analyzed by GC to assess the reaction progress and selectivity. The product concentration was determined by relative integration (by GC) of the product peaks against mesitylene, in accordance with calibration curves. Two trials were run for all experiments. 335 50 y = 6.0309x R² = 0.9812 40 30 20 10 (ITMe)Ni(styrene)2 (1k) 0 0 5 10 15 20 25 30 Time (min) Figure C.16. Initial rate of the formation of 4aa versus time (min). 250 200 150 100 50 (ITMe)Ni(styrene)2 (1k) 0 0 30 60 90 120 150 180 Time (min) Figure C.17. Full reaction profile for the formation of 4aa versus time (min). Table C.8. [4aa] (mM) and selectivity (l:b) of 4aa formed. Time (min) [4aa] (mM) Selectivity (l:b) 1 2.8±0.9 1:6.7 2 8±1 1:12 3 16±1 1:16 4 24±5 1:17 5 33±12 1:19 336 [4aa] (mM) [4aa] (mM) 7 40±6 1:20 10 48±2 1:23 20 67.69±0.04 1:23 30 86±12 1:20 45 105±22 1:15 60 108±18 1:12 90 129±25 1:8.1 120 133±24 1:6.2 180 151±17 1:4.1 50 y = 1.5609x R² = 0.9971 40 30 20 10 (IMes)Ni(styrene)2 (1e) 0 0 5 10 15 20 25 30 Time (min) Figure C.18. Initial rate of the formation of 4aa versus time (min). 337 [4aa] (mM) 250 200 150 100 50 (IMes)Ni(styrene)2 (1e) 0 0 30 60 90 120 150 180 Time (min) Figure C.19. Full reaction profile for the formation of 4aa versus time (min). Table C.9. [4aa] (mM) and selectivity (l:b) of 4aa formed. Time (min) [4aa] (mM) Selectivity (l:b) 1 1.1±0.6 1:2.1 2 2.524±0.007 1:4.0 3 4.4±0.3 1:5.9 4 5.8±0.1 1:7.7 5 7.7±0.9 1:8.0 10 16±1 1:9.7 15 25.6±0.4 1:10 21 36.9±0.7 1:9.4 30 52±3 1:8.7 40 86±5 1:8.0 60 105±7 1:7.5 80 145±4 1:7.2 100 170.01±0.03 1:7.4 120 203.56±0.04 1:7.9 150 194.51±0.03 1:8.0 180 182.02±0.03 1:8.1 338 [4aa] (mM) 50 y = 1.0472x R² = 0.9983 40 30 20 10 (ClIMes)Ni(styrene)2 (1l) 0 0 5 10 15 20 25 30 Time (min) Figure C.20. Initial rate of the formation of 4aa versus time (min). 250 200 150 100 50 (ClIMes)Ni(styrene)2 (1l) 0 0 30 60 90 120 150 180 Time (min) Figure C.21. Full reaction profile for the formation of 4aa versus time (min). Table C.10. [4aa] (mM) and selectivity (l:b) of 4aa formed. 339 [4aa] (mM) [4aa] (mM) Time (min) [4aa] (mM) Selectivity (l:b) 0.5 0.314±0.002 1:0.7 1 0.8±0.1 1:0.9 1.5 1.2±0.1 1:1.2 2 1.9±0.1 1:1.6 2.5 2.19±0.02 1:1.7 3 2.8±0.2 1:2.0 3.5 3.39±0.06 1:2.3 4 3.86±0.01 1:2.5 5 4.77±0.06 1:2.9 10 11±1 1:4.3 15 15.9±0.9 1:5.1 20 20.9±0.9 1:5.4 30 33.3±0.5 1:6.1 45 52±6 1:6.0 60 67±2 1:5.6 90 111±2 1:5.5 120 148±5 1:5.4 150 181±21 1:5.9 180 169±8 1:6.0 340 50 40 30 20 10 (SIMes)Ni(styrene)2 (1m) 0 0 5 10 15 20 25 30 Time (min) Figure C.22. Initial rate of the formation of 4aa versus time (min). 250 200 150 100 50 (SIMes)Ni(styrene)2 (1m) 0 0 30 60 90 120 150 180 Time (min) Figure C.23. Full reaction profile for the formation of 4aa versus time (min). Table C.11. [4aa] (mM) and selectivity (l:b) of 4aa formed. Time (min) [4aa] (mM) Selectivity (l:b) 2 7±2 27:1 4 19±6 48:1 6 31±7 70:1 8 49±13 76:1 10 55±8 78:1 341 [4aa] (mM) [4aa] (mM) 15 96±24 78:1 20 108±40 71:1 30 200±36 82:1 45 207±16 86:1 60 216±33 78:1 90 214±24 79:1 120 196±17 81:1 150 219±46 78:1 180 214±31 75:1 50 y = 2.2142x R² = 0.9711 40 30 20 10 (MeIMes)Ni(styrene)2 (1n) 0 0 5 10 15 20 25 30 Time (min) Figure C.24. Initial rate of the formation of 4aa versus time (min). 342 [4aa] (mM) 250 200 150 100 50 (MeIMes)Ni(styrene)2 (1n) 0 0 30 60 90 120 150 180 Time (min) Figure C.25. Full reaction profile for the formation of 4aa versus time (min). Table C.12. [4aa] (mM) and selectivity (l:b) of 4aa formed. Time (min) [4aa] (mM) Selectivity (l:b) 0.5 0.4±0.2 0:1 1 0.8±0.2 1:2.1 2.5 2.9±0.3 1:10 3 4.6±0.4 1:6.4 3.5 6.1±0.9 1:6.7 4 7.4±0.4 1:17 4.5 8.9±0.5 1:20 5 11.5±0.7 1:26 10 25±1 1:42 15 36±3 1:53 20 52±3 1:56 30 81±7 1:59 45 129±7 1:49 60 174±14 1:49 90 225±4 1:48 120 225±1 1:47 150 219±16 1:47 180 222±6 1:49 343 [4aa] (mM) 50 (IPr)Ni(styrene)2 (1o) 40 y = 0.1355x R² = 0.9903 30 20 10 0 0 5 10 15 20 25 30 Time (min) Figure C.26. Initial rate of the formation of 4aa versus time (min). 250 (IPr)Ni(styrene)2 (1o) 200 150 100 50 0 0 30 60 90 120 150 180 Time (min) Figure C.27. Full reaction profile for the formation of 4aa versus time (min). Table C.13. [4aa] (mM) and selectivity (l:b) of 4aa formed. Time (min) [4aa] (mM) Selectivity (l:b) 344 [4aa] (mM) [4aa] (mM) 5 1.66±1 0:1 10 1.59 1:4.5 15 3.2±0.7 1:10.8 20 4.6±0.4 1:10.0 30 5.7±0.1 1:11.5 45 6.5±0.4 1:10.0 60 8.7±0.4 1:9.6 90 12.6±0.1 1:8.4 120 14.0±0.1 1:6.6 150 21±4 1:5.2 180 24.1±0.9 1:4.3 50 y = 6.0309x y = 4.9524x y = 2.2142x y = 1.5609x y = 1.0472x R² = 0.9812 R² = 0.9913 R² = 0.9711 R² = 0.9971 R² = 0.9983 40 y = 0.1355x ITMe (1k) R² = 0.9903 SIMes (1m) 30 MeIMes (1n) ClIMes (1l) 20 IMes (1e) 10 IPr (1o) 0 0 5 10 15 20 25 30 Time (min) Figure C.28. Compiled initial rates data of the formation of 4aa versus time (min) catalyzed by 1e, 1k-1o. 345 [4aa] (mM) 250 200 (SIMes)Ni(styrene)2 (1m) 150 (MeIMes)Ni(styrene)2 (1n) (ITMe)Ni(styrene)2 (1k) 100 (IMes)Ni(styrene)2 (1e) (ClIMes)Ni(styrene)2 (1l) (IPr)Ni(styrene)2 (1o) 50 0 0 30 60 90 120 150 180 Time (min) Figure C.29. Compiled full reaction profiles for the formation of 4aa versus time (min) catalyzed by 1e, 1k-1o. Table C.14. [4aa] (mM) and selectivity (l:b) of 4aa formed. Initial rate Catalyst %VBur TEP Relative Rate (mM/min) (ITMe)Ni(styrene)2 (1k) 26.1 2051.7 6.0309 45 (SIMes)Ni(styrene)2 (1m) 34.3 2051.5 4.9524 37 (MeIMes)Ni(styrene)2 (1n) 34.4 2052.0 2.2142 16 (IMes)Ni(styrene)2 (1e) 33.7 2050.0 1.5609 12 (ClIMes)Ni(styrene)2 (1l) 34.2 2055.1 1.0472 7.7 (IPr)Ni(styrene)2 (1o) 36.9 2051.5 0.1355 1 TEP, Tolman electronic parameter b. Variable Time Normalization Analysis Kinetics Three separate experiments were conducted in duplicate to visualize whether or not the catalyst (1e) decomposed or experienced product inhibition throughout the course of the reaction using the method of variable time normalization analysis (VTNA).157 Experiments A and B: 346 [4aa] (mM) Experiment C: General Procedure: In a nitrogen-filled glovebox, 1e (7.6 mg, 0.013 mmol, 1.0 equiv) was directly weighed into a 1-dram scintillation vial equipped with a stir bar and toluene (1.2 mL) was added using a disposable 1 mL syringe. 2a (18 or 30 µL, 0.16 or 0.26 mmol, 12 or 20 equiv) and mesitylene (15 µL, 0.11 mmol) were added to the vial using a 50-µL syringe and then sealed with a septum cap. The reaction was brought out of the glovebox and 3a (33 or 54 µL, 0.18 or 0.29 mmol, 14 or 22 equiv) and 4aa (0 or 30 µL, 0 or 0.11 mmol, 0 or 8.5 equiv) were added via a 100- μL syringe, and the vial was placed on an aluminum vial block preheated to 80 °C. Throughout the course of the reaction, 20 μL aliquots were removed with a 25-μL syringe and filtered into a GC vial through Celite and diluted with hexanes. The filtrate was analyzed by GC to assess the reaction progress and selectivity. The product concentration was determined by relative integration (by GC) of the product peaks against mesitylene, in accordance with calibration curves. Two trials were run for all experiments. The initial concentrations of 2a, 3a, and 4aa are listed in the table below for the corresponding experiment. Table C.15. Corresponding amounts of 2a, 3a, 4aa, and 1e that were used for each experiment. Experiment [2a]0 (mM) [3a]0 (mM) [4aa]0 (mM) [1e] (mM) A 218 240 0 11.1 B 131 144 0 11.1 347 C 131 144 87.3 11.1 250 200 150 100 50 A 0 0 50 100 150 Time (min) Figure C.30. Reaction profile of Experiment A monitoring the formation of 4aa versus time (min). Table C.16. Concentration of 4aa (mM) and selectivity (l:b) over time for Experiment A. Time (min) [4aa] (mM) Selectivity (l:b) 6 10.5 ± 0.9 1:81 10 18 ± 1 1:65 20 40 ± 2 1:68 30 62 ± 1 1:69 40 84 ± 5 1:67 50 100 ± 5 1:65 60 120 ± 23 1:59 70 155 ± 14 1:57 80 175 ± 10 1:57 90 202 ± 8 1:55 100 204 ± 8 1:55 110 188.1 ± 0.4 1:55 120 207 ± 4 1:60 130 202 ± 5 1:53 140 206 ± 8 1:54 348 [4aa] mM 250 200 150 100 50 B 0 0 50 100 150 Time (min) Figure C.31. Reaction profile of Experiment B monitoring the formation of 4aa versus time (min). 250 200 150 100 50 B 0 0 50 100 150 Time (min) Figure C.32. Reaction profile of Experiment B post 4aa-adjustment (+87 mM, assumes 40% product at time zero) and time-adjustment (+43 m) monitoring the formation of 4aa versus time (min). 349 [4aa] mM [4aa] mM 250 200 150 100 50 A B 0 0 50 100 150 Time (min) Figure C.33. Reaction profile overlay of Experiment A and Experiment B monitoring the formation of 4aa versus time (min). 250 200 150 100 50 A B 0 0 50 100 150 Time (min) Figure C.34. Reaction profile of Experiment B post 4aa-adjustment (+83 mM, this assumes 40% of 4aa has already formed prior to the experiment) and time-adjustment (+43 min) monitoring the formation of [4aa] (mM) versus time (min). Table C.17. Time-adjustment (min), concentration of 4aa (mM), [4aa] adjustment (mM), and selectivity (l:b) over time for Experiment B. 350 [4aa] mM [4aa] mM Adjusted Time Adjusted [4aa] Selectivity Time (min) [4aa] (mM) (min, +43 min) (mM, +83 mM) (l:b) 6 49 13.3 ± 0.9 96.3 1:112 10 53 22 ± 2 105 1:150 20 63 47 ± 3 130 1:98 30 73 75 ± 1 158 1:114 40 83 96 ± 4 179 1:109 50 93 126 ± 19 209 1:98 60 103 133 ± 15 216 1:90 70 113 119.7 ± 0.4 202.6 1:87 80 123 133 ± 4 216 1:86 90 133 126 ± 12 209 1:83 100 143 135 ± 3 218 1:83 Overlaying Experiment A and B shows no deviation in kinetic profiles, indicating that neither catalyst decomposition nor product inhibition is occurring throughout the reaction. 250 200 150 100 50 C 0 0 50 100 150 Time (min) Figure C.35. Reaction profile of Experiment C monitoring the formation of 4aa versus time (min). 351 [4aa] mM 250 200 150 100 50 C 0 0 50 100 150 Time (min) Figure C.36. Reaction profile of Experiment C post time-adjustment (+50 min) kinetic profile of Experiment C monitoring the formation of 4aa versus time (min). Table C.18. Time-adjustment (min), concentration of 4aa (mM), and selectivity (l:b) over time for Experiment C. Adjusted Time Time (min) [4aa] (mM) Selectivity (l:b) (min, +50 min) 0.5 50.5 100 ± 22 1:52 6 56 101 ± 9 1:41 10 60 96 ± 2 1:35 20 70 140 ± 26 1:24 30 80 181 ± 46 1:17 40 90 205 ± 23 1:16 50 100 211 ± 6 1:16 60 110 205 ± 34 1:16 70 120 196 ± 30 1:28 80 130 212 ± 7 1:17 352 [4aa] mM 250 200 150 100 A 50 C 0 0 50 100 150 Time (min) Figure C.37. Overlay of the reaction profiles of Experiment A and C for the formation of 4aa versus time (min). 250 200 150 100 A 50 C 0 0 50 100 150 Time (min) Figure C.38. Overlay of the reaction profiles of Experiment A and C (post time-adjustment +50 min) for the formation of 4aa versus time (min). Overlaying Experiment A and C shows no deviation in kinetic profiles, further indicating that product inhibition is not occurring throughout the reaction. C.1.11. Cyclic Voltammetry of (NHC)Ni(styrene)2 Complexes 353 [4aa] mM [4aa] mM In a nitrogen-filled glovebox, electrochemical measurements were made with potentiostat 561 (Bio-Logic SP300) using a typical three-electrode setup (glassy carbon working electrode, Ag/Ag+ wire reference, and platinum wire counter electrode) in a 20 mL glass vial equipped with a magnetic stir bar. An electrolyte solution of [NBu4][ClO4] was prepared in DMF (0.1 mM). The nickel complex of interest (~5 mg) was dissolved in the electrolyte solution (10 mL). Current was reported in mA, while all potentials were reported in volts (V) against Fc+/Fc redox couple, at a scan rate of 100 mV/s. All scans reported are oxidative scans. Sweeping from left to right or right to left is specified for each complex. 0.01 0.01 0.00 0.00 (ITMe)Ni(styrene) (1k) -0.01 -1.5 -1.2 -0.9 -0.6 -0.3 0 0.3 0.6 0.9 E (V vs. Fc+/Fc) Figure C.39. Cyclic voltammogram of (ITMe)Ni(styrene)2 (1k) in a 0.01 M [NBu4][ClO4] solution in DMF at 100 mV•s- taken at 273 K. Oxidative scan sweeping from left to right. 0.01 0.01 0.00 0.00 (IMes)Ni(styrene)2 (1e) -0.01 -1.5 -1.2 -0.9 -0.6 -0.3 0 0.3 0.6 0.9 E (V vs. Fc+/Fc) 354 i (mA) i (mA) Figure C.40. Cyclic voltammogram of (IMes)Ni(styrene)2 (1e) in a 0.01 M [NBu4][ClO4] solution in DMF at 100 mV•s- taken at 273 K. Oxidative scan sweeping from right to left. 0.01 0.01 0.00 0.00 (IPr)Ni(styrene)2 (1o) -0.01 -1.5 -1.2 -0.9 -0.6 -0.3 0 0.3 0.6 0.9 E (V vs. Fc+/Fc) Figure C.41. Cyclic voltammogram of (IPr)Ni(styrene)2 (1o) in a 0.01 M [NBu4][ClO4] solution in DMF at 100 mV•s- taken at 273 K. Oxidative scan sweeping from right to left. 0.01 0.01 0.00 0.00 (MeIMes)Ni(styrene)2 (1n) -0.01 -1.5 -1.2 -0.9 -0.6 -0.3 0.0 0.3 0.6 0.9 E (V vs. Fc+/Fc) Figure C.42. Cyclic voltammogram of (MeIMes)Ni(styrene)2 (1n) in a 0.01 M [NBu4][ClO4] solution in DMF at 100 mV•s- taken at 273 K. Oxidative scan sweeping from left to right. 355 i (mA) i (mA) 0.01 0.01 0.00 0.00 (SIMes)Ni(styrene)2 (1m) -0.01 -1.5 -1.2 -0.9 -0.6 -0.3 0 0.3 0.6 0.9 E (V vs. Fc+/Fc) Figure C.43. Cyclic voltammogram of (SIMes)Ni(styrene)2 (1m) in a 0.01 M [NBu4][ClO4] solution in DMF at 100 mV•s- taken at 273 K. Oxidative scan sweeping from right to left. C.1.12. Other Mechanistic Reactions d. Stoichiometric Experiments Between 1e and 3a Monitored by 1H NMR In a nitrogen-filled glovebox, 1e (4.6 mg, 0.0080 mmol, 1.0 equiv) was weighed out directly into a J-Young NMR tube and solvated in C7D8 (0.75 mL, 0.010 M) using a disposable 1- mL syringe. To this solution was added 3a (3.0 µL, 0.016 mmol, 2.0 equiv) and mesitylene (3.0 µL, 0.022 mmol) using a 10-µL syringe. The NMR tube was sealed, removed from the glovebox, and placed in a pre-heated NMR instrument at 100 °C. Reaction progress was monitored by 1H NMR. Full conversion of 3a was observed within 5 min. The reaction was further heated at 100 °C for a total 1 h, during which no further change in product distribution was observed. The 356 i (mA) reaction was cooled to room temperature and opened to air. A 5-µL aliquot was removed with a 10-µL syringe and filtered into a GC vial through Celite and diluted with hexanes into a GC vial and analyzed by GC to assess the reaction progress and selectivity. The product concentration was determined by relative integration (by GC) of the product peaks against durene, in accordance with calibration curves. Figure C.44. 1H NMR spectrum of the reaction between 1e and 3a after heating at 100 °C for 1 h recorded in C7D8 at 25 °C. A distribution of 1e, 1g, and 4aa were observed by 1H NMR. Ethylbenzene was also observed by GC (which could be a product of hydrogenation and would account for the H mass balance); however, the peaks corresponding to ethylbenzene are not visible by 1H NMR. 39% of the pre-coordinated styrene on 1e reacted to form 4aa determined by GC using mesitylene as an internal standard. Approximately a 2.0:1.4:1.0 (4aa:1e:1g) ratio was found by integrating the corresponding peaks at 5.02 ppm, 3.19 ppm, and -2.25 ppm, respectively. C.1.12. Crystallographic data for 1g 357 Figure C.45. Molecular structure of (IMes)Ni(µ-H–SiPh2)2Ni(IMes) (1g). Hydrogen atoms except for Ni–H–Si are omitted for clarity. Diffraction intensities for 1g were collected at 173 K on a Bruker Apex2 CCD DUO diffractometer using MoK radiation, ƛ = 0.71073 Å. Space group was determined based on systematic absences. Absorption correction was applied by SADABS.288 Structure was solved by direct methods and Fourier techniques and refined on F2 using full matrix least-squares procedures. All non-H atoms were refined with anisotropic thermal parameters. All H atoms were found on the residual density maps and refined with isotropic thermal parameters except those in the terminal Me groups. The H atoms in these Me groups were treated in calculated positions in a rigid 358 group model but with ability for rotation of these–CH3 groups around the corresponding C-C bonds (HFIX 138). All calculations were performed by the Bruker SHELXL-2014/7 package.289 Crystallographic Data for 1g: C66H70N4Ni2Si2, M = 1092.86, 0.16 x 0.14 x 0.14 mm, T = 173(2) K, Monolinic, space group P21/c, a = 13.1040(7) Å, b = 18.5796(10) Å, c = 13.4685(7) Å, β = 118.222(1)°, V = 2889.3(3) Å3, Z = 2, Dc = 1.256 Mg/m3, μ(Mo) = 0.737 mm-1, F(000) = 1156, 2θmax = 56.58°, 24301 reflections, 7087 independent reflections [Rint = 0.0331], R1 = 0.0309, wR2 = 0.0772 and GOF = 1.029 for 7087 reflections (414 parameters) with I>2σ(I), R1 = 0.0420, wR2 = 0.0824 and GOF = 1.029 for all reflections, max/min residual electron density +0.381/-0.270 eÅ-3. C.1.13. NMR and IR Spectra b. Nickel Complexes Figure C.46. 1H NMR spectrum of (IMes)Ni(µ-H–SiPh2)2Ni(IMes) (1g) recorded in C6D6 at 298 K. 359 Figure C.47. 13C{1H} NMR spectrum of (IMes)Ni(µ-H–SiPh2)2Ni(IMes) (1g) recorded in C6D6 at 298 K. Figure C.48. 29Si NMR spectrum of (IMes)Ni(µ-H–SiPh2)2Ni(IMes) (1g) recorded in C6D6 at 298 K. 360 Figure C.49. COSY NMR spectrum of (IMes)Ni(µ-H–SiPh2)2Ni(IMes) (1g) recorded in C6D6 at 298 K. Figure C.50. HSQC NMR spectrum of (IMes)Ni(µ-H–SiPh2)2Ni(IMes) (1g) recorded in C6D6 at 298 K. 361 Figure C.51. IR spectrum of (IMes)Ni(µ-H–SiPh2)2Ni(IMes) (1g) recorded as a KBr pellet at 298 K. Figure C.52. 1H NMR spectrum of (4-methoxystyrene)2Ni(IMes) (1h) recorded in C6D6 at 298 K. 362 Figure C.53. 13C{1H} NMR spectrum of (4-methoxystyrene)2Ni(IMes) (1h) recorded in C6D6 at 298 K. Figure C.54. COSY NMR spectrum of (4-methoxystyrene)2Ni(IMes) (1h) recorded in C6D6 at 298 K. 363 Figure C.55. HSQC NMR spectrum of (4-methoxystyrene)2Ni(IMes) (1h) recorded in C6D6 at 298 K. Figure C.56. IR spectrum of (4-methoxystyrene)2Ni(IMes) (1h) recorded as a KBr pellet at 298 K. 364 Figure C.57. 1H NMR spectrum of (4-fluorostyrene)2Ni(IMes) (1i) recorded in C6D6 at 298 K. Figure C.58. 13C{1H} NMR spectrum of (4-fluorostyrene)2Ni(IMes) (1i) recorded in C6D6 at 298 K. 365 Figure C.59. 19F NMR spectrum of (4-fluorostyrene)2Ni(IMes) (1i) recorded in C6D6 at 298 K. Figure C.60. COSY NMR spectrum of (4-fluorostyrene)2Ni(IMes) (1i) recorded in C6D6 at 298 K. 366 Figure C.61. HSQC NMR spectrum of (4-fluorostyrene)2Ni(IMes) (1i) recorded in C6D6 at 298 K. Figure C.62. IR spectrum of (4-fluorostyrene)2Ni(IMes) (1i) recorded as a KBr pellet at 298 K. 367 Figure C.63. 1H NMR spectrum of (4-trifluoromethylstyrene)2Ni(IMes) (1j) recorded in C6D6 at 298 K. Figure C.64. 13C{1H} NMR spectrum of (4-trifluoromethylstyrene)2Ni(IMes) (1j) recorded in C6D6 at 298 K. 368 Figure C.65. 19F NMR spectrum of (4-trifluoromethylstyrene)2Ni(IMes) (1j) recorded in C6D6 at 298 K. Figure C.66. COSY NMR spectrum of (4-trifluoromethylstyrene)2Ni(IMes) (1j) recorded in C6D6 at 298 K. 369 Figure C.67. HSQC NMR spectrum of (4-trifluoromethylstyrene)2Ni(IMes) (1j) in C6D6 at 298 K. Figure C.68. IR spectrum of (4-trifluoromethylstyrene)2Ni(IMes) (1j) recorded as a KBr pellet at 298 K. 370 Figure C.69. 1H NMR spectrum of (styrene)2Ni(ITMe) (1k) recorded in C6D6 at 298. Figure C.70. 13C{1H} NMR spectrum of (styrene)2Ni(ITMe) (1k) recorded in C6D6 at 298. 371 Figure C.71. COSY NMR spectrum of (styrene)2Ni(ITMe) (1k) recorded in C6D6 at 298. Figure C.72. HSQC NMR spectrum of (styrene)2Ni(ITMe) (1k) recorded in C6D6 at 298. 372 Figure C.73. DOSY NMR spectrum of (styrene)2Ni(ITMe) (1k) recorded in C6D6 at 298. 373 APPENDIX D SUPPLEMENTARY CONTENT FOR CHPATER V Experimental details D.1.1. Materials and Methods All syntheses and manipulations were carried out under nitrogen using standard Schlenk (vacuum 10-2 mbar) techniques or in a nitrogen-filled glovebox unless otherwise indicated. All reagents and solvents were used after drying and stored under nitrogen, unless otherwise indicated. Tetrahydrofuran (THF; Fisher Chemical; HPLC grade, unstabilized), hexanes (Fisher Chemical; HPLC grade), and diethyl ether (B&J Brand; HPLC grade, unstabilized) were dispensed under nitrogen from an LC Technology SP-1 solvent system. Benzene (ACS grade) and pentane (HPLC grade) were refluxed overnight with CaH2 and distilled under nitrogen before use. The dried solvents were thereafter stored on activated 4Å molecular sieves under nitrogen. C6D6 and CDCl3 were purchased from Cambridge Isotope Laboratories, degassed by freeze-pump-thaw, and thereafter stored on activated 4Å molecular sieves under nitrogen. All stock solutions were prepared by mass and were dispensed into the reaction vessel by difference from syringe, as detailed in the procedure for each experiment. ITMe263, IMes264, MeIMes290, MeIPr290, Ni(COD)(DQ)291, 1a6, and 1b21 were synthesized via reported procedures. D.1.2. General Experimental Nuclear magnetic resonance (NMR) spectra were collected at room temperature (298 K) unless otherwise stated on a Bruker AV-III HD 600 NMR (600.13 MHz for 1H; 150.90 MHz for 13C; 564.69 MHz for 19F; 119.23 MHz for 29Si; 92.12 MHz for 2H), Bruker Avance-III HD 500 NMR (499.90 MHz for 1H; 126 MHz for 13C; 471 MHz for 19F; 99 MHz for 29Si), or Varian Inova 500 NMR (499.90 MHz for 1H; 126 MHz for 13C; 471 MHz for 19F; 99 MHz for 29Si). 1H and 13C spectra were referenced to the residual solvent peak (CDCl3: 1H δ = 7.26 ppm, 13C δ = 77.16 ppm; C D : 1H δ = 7.16 ppm, 136 6 C δ = 128.06 ppm, CD3CN: 1H δ = 1.94 ppm, 13C δ = 1.32 ppm (NCCD3)). Chemical shifts for 1H and 13C spectra are reported in parts per million (ppm, δ) relative to tetramethylsilane at 0.00 ppm. Peaks are characterized as follows: s (singlet), d (doublet), t (triplet), 374 q (quartet), pent (pentet), hept (heptet), m (multiplet), qd (quartet of doublets), br (broad), app (apparent), and/or ms (multiple signals). Coupling constants, J, are reported in Hz. Infrared (IR) spectroscopy for air-stable organic compounds was performed on an Agilent Nicolet 6700 FT-IR using the ATR sampling technique. IR spectra for air-sensitive nickel complexes were recorded as self-supported pellets diluted with KBr using a Bruker Alpha II FT- IR spectrometer that is housed in a nitrogen-filled glovebox. All bands are reported in wavenumbers (cm-1) and are described as broad (br), strong (s), medium (m), and weak (w). D.1.3. Monitoring Isomerization by GC a. Evaluation of NHCs In a nitrogen-filled glovebox, a stock solution of Ni(COD)2 (0.0025 g, 0.0091 mmol, 0.050 equiv added to each vial) and the corresponding NHC (0.0091 mmol, 0.050 equiv added to each vial) was prepared in toluene using volumetric glassware and distributed into a 1-dram vial using a disposable 1-mL syringe while stirring. To this stirring solution was added 1a (24 µL, 0.18 mmol, 1.0 equiv) using a 50-µL syringe and separate stock solutions of HSiPh3 (0.0024 g, 0.0091 mmol, 0.050 equiv added to each vial) and of durene (0.050 g, 0.037 mmol added to each vial) in toluene were also distributed to each vial using a disposable 1-mL syringe to obtain a total volume of 1.1 mL. The vial was sealed with a septum cap, brought out of the glovebox, and placed onto a preheated vial block at 60 °C. Throughout the course of the reaction, 20 µL aliquots were removed with a 25-µL syringe, filtered into a GC vial through Celite, and diluted with hexanes. The filtrate from the Celite plug was analyzed by GC to assess the reaction progress and selectivity. The product conversion was determined by relative integration (by GC) of the product peaks. All trials were run in duplicate. 375 100 IPr 80 60 40 20 0 0 1 2 3 4 5 Time (h) Figure D.1. Full kinetic profile of the formation of 2a versus time (min) using IPr as the NHC. 50 40 30 20 10 IPr 0 0 1 2 3 4 5 Time (h) Figure D.2. Full selectivity (E/Z) profile of the formation of 2a versus time (min) using IPr as the NHC. 376 % Conversion to 2a Selectivity (E/Z) Table D.1. % Conversion to 2a and selectivity (E:Z) of 2a formed using IPr as the NHC. Time (h) % Conversion to 2a Selectivity (E:Z) (std error) 0.13 0.88±0.08 19:1 (4) 0.33 1.59±0.07 17.0:1 (0.1) 0.53 2.2±0.2 19:1 (3) 0.73 3.0±0.3 20:1 (3) 0.93 3.8±0.5 21:1 (3) 1.13 4.7±0.7 23:1 (2) 1.33 5.8±0.9 24:1 (2) 1.53 7±1 26:1 (1) 1.73 8±1 27:1 (1) 1.93 10±1 29:1 (2) 2.43 14±2 25:1 (1) 2.93 19±2 34:1 (1) 3.93 30±4 35:1 (3) 4.93 46±6 41:1 (3) 100 ClIPr 80 60 40 20 0 0 1 2 3 4 5 Time (h) Figure D.3. Full kinetic profile of the formation of 2a versus time (min) using ClIPr as the NHC. 377 % Conversion to 2a 50 40 30 20 10 ClIPr 0 0 1 2 3 4 5 Time (h) Figure D.4. Full selectivity (E/Z) profile of the formation of 2a versus time (min) using ClIPr as the NHC. Table D.2. % Conversion to 2a and selectivity (E:Z) of 2a formed using ClIPr as the NHC. Time (h) % Conversion to 2a Selectivity (E:Z) (std erorr) 0.13 0.7±0.1 16:1 (9) 0.33 1.0±0.1 23.5:1 (0.7) 0.53 1.3±0.1 23:1 (2) 0.73 1.8±0.2 12.5:1 (0.7) 0.93 2.11±0.01 18:1 (7) 1.13 2.2±0.2 23:1 (5) 1.33 2.4±0.3 23:1 (1) 1.53 2.7±0.3 23:1 (1) 1.73 2.9±0.2 22.2:1 (0.8) 1.93 3.1±0.4 22.0:1 (0.6) 2.43 3.7±0.5 14:1 (1) 2.93 4.1±0.4 22.9:1 (0.1) 3.93 4.8±0.5 17.4:1 (0.8) 4.93 5.6±0.4 17.4:1 (0.8) 378 Selectivity (E/Z) 100 80 60 40 20 MeIPr 0 0 1 2 3 4 5 Time (h) Figure D.5. Full kinetic profile of the formation of 2a versus time (min) using MeIPr as the NHC. 50 40 30 20 10 MeIPr 0 0 1 2 3 4 5 Time (h) Figure D.6. Full selectivity (E/Z) profile of the formation of 2a versus time (min) using MeIPr as the NHC. 379 % Conversion to 2a Selectivity (E/Z) Table D.3. % Conversion to 2a and selectivity (E:Z) of 2a formed using MeIPr as the NHC. Time (h) % Conversion to 2a Selectivity (E:Z) 0.13 8 47 0.33 37 49 0.53 78 46 0.73 99 31 0.93 98 29 1.13 99 28 1.33 99 28 1.53 99 29 1.73 98 28 1.93 98 29 2.43 98 28 2.93 98 28 3.93 98 29 4.93 97 28 100 80 IPr ClIPr 60 MeIPr 40 20 0 0 1 2 3 4 5 Time (h) Figure D.7. Full kinetic profile of the formation of 2a versus time (min). 380 % Conversion to 2a 50 40 30 20 IPr 10 IPr Cl IPr Me 0 0 1 2 3 4 5 Time (h) Figure D.8. Full selectivity (E/Z) profile of the formation of 2a versus time (min). b. Evaluation of Ni(0) Source In a nitrogen-filled glovebox, Ni(COD)2 (0.0016 g, 0.0060 mmol, 0.050 equiv) or Ni(COD)(DQ) (0.0020 g, 0.0060 mmol, 0.050 equiv) were weighed directly into a 1-dram vial equipped with a stir bar. A stock solution of MeIPr was prepared in the corresponding solvent and distributed into each vial with Ni using a disposable 1-mL syringe. A separate stock solution of HSiPh3 (0.0016 g, 0.0.0062 mmol, 0.050 equiv added to each vial) and cyclooctane (2.5 µL, 0.019 mmol added to each vial) was prepared in toluene and distributed into each vial using a disposable 1-mL syringe. The vial was sealed with a septum cap, brought out of the glovebox, and placed onto a preheated vial block at 40 °C. Throughout the course of the reaction, 20 µL aliquots were removed with a 25-µL syringe, filtered into a GC-MS vial through Celite, and diluted with hexanes. The filtrate from the Celite plug was analyzed by GC-MS to assess the reaction progress and selectivity. The product concentration was determined by relative integration (by GC-MS) of the product peaks against cyclooctane, in accordance with calibration curves. Two trials were run for all experiments. 381 Selectivity (E/Z) 100 4-Ph-1-butene 3-Ph-1-butene (E&Z) 80 2-Ph-1-butene (E&Z) 60 40 20 0 0 1 2 3 4 5 6 Time (h) Figure D.8. Full kinetic profile of the isomerization of 1b to A-2b and B-2b versus time (min) using Ni(COD)2 in toluene. Table D.5. Concentration of 1b, A-2b, and B-2b formed using Ni(COD)2 in toluene. Time (h) [1b] (mM) [A-2b] (mM) [B-2b] (mM) 0.4 100.7±0.2 1.5±0.2 0 1.0 93.4±0.6 8±3 0 2.0 60 40 0.8 2.8 25±6 74±4 3.5±0.9 6.0 0.6 23 88 382 [alkene] (mM) 100 4-Ph-1-butene 3-Ph-1-butene (E&Z) 80 2-Ph-1-butene (E&Z) 60 40 20 0 0 1 2 3 4 5 6 Time (h) Figure D.9. Full kinetic profile of the isomerization of 1b to A-2b and B-2b versus time (min) using Ni(COD)(DQ) in toluene. Table D.6. Concentration of 1b, A-2b, and B-2b formed using Ni(COD)(DQ) in toluene. Time (h) [1b] (mM) [A-2b] (mM) [B-2b] (mM) 0.4 42 41 19 1.0 1.0 51 58 2.0 1.0 42 69 2.8 0 37 76 6.0 0 27 88 No isomerization activity was observed using cyclohexane, n-octane, or hexane as the solvent medium due to catalyst insolubility at 40 °C. D.1.4. Hydrosilylation a. Authentic Hydrosilylation Product (4a-4d) Characterization and Isolation In a nitrogen-filled glovebox, Ni(COD)2 (0.010 g, 0.036 mmol, 0.050 equiv), MeIMes (0.012 g, 0.036 mmol, 0.050 equiv), and HSiPh3 (0.19 g, 0.73 mmol, 1.0 equiv) were weighed directly into a 1-dram vial equipped with a stir bar. To this vial was added toluene (3.0 mL) using 383 [alkene] (mM) a disposable 6-mL syringe, the vial was sealed with a septum cap, brought out of the glovebox, and injected with 1b (0.10 mL, 0.67 mmol, 1.0 equiv) using a 250-µL syringe, and placed onto a preheated vial block at 100 °C. After 24 h, an aliquot (10 µL) of the reaction was removed using a 25-µL syringe, filtered through Celite, and washed with hexanes directly into a GC vial to assess product selectivity. The reaction was quenched by cooling in a liquid N2 bath, thawing at room temperature, and the crude reaction was concentrated under reduced pressure. The resulting crude product was purified by column chromatography (silica, 0-5:95%, benzene/hexanes) and the product isomers were isolated separately to determine the product 1H NMR peaks and GC/GC-MS peak retention times. Products 4a, 4c and 4d were successfully isolated and characterized by 1H NMR. Figure D.10. 1H NMR of 4a recorded in CDCl3 at 298 K. 384 Figure D.11. 1H NMR of 4c (pink circles) and 4d (purple triangles) recorded in CDCl3 at 298 K. Figure D.12. 1H NMR of 4d recorded in CDCl3 at 298 K. b. Alkene Hydrosilylation Optimization 385 In a nitrogen-filled glovebox, Ni(COD)(DQ) (0.0040 g, 0.012 mmol, 0.10 equiv), MeIPr (0.0025 g, 0.0060 mmol, 0.050 equiv), and the corresponding NHC (MeIMes or IMes) were weighed directly into a 1-dram scintillation vial equipped with a stir bar. To this vial was added toluene (0.60 mL), and a previously prepared stock solution of 3a (0.062 g, 0.24 mmol, 1.0 equiv) and cyclooctane (10 µL, 0.074 mmol) in toluene was distributed to obtain a total volume of 1.0 mL. The vial was sealed with a septum cap, removed from the glovebox, injected with 1b (36 µL, 0.24 mmol, 1.0 equiv) and placed on a preheated vial block at 80 °C. After 24 h, an aliquot (~20 µL) was removed using a 25-µL syringe, filtered into a GC-MS vial through Celite, and diluted with hexanes. The filtrate from the Celite plug was analyzed by GC-MS to assess the reaction progress and selectivity. The product concentration was determined by relative integration (by GC- MS) of the alkene against cyclooctane, in accordance with calibration curves. Two trials were run for all experiments. Table D.7. Reaction conditions of remote hydrosilylation reactions tested. % conversion of 1b to Selectivity Entry NHC HS products (4a/4b-4d) 1 MeIMes 75±1% 0.9:1 2 IMes 53±3% 1.9:1 c. Solvent Screen for the Hydrosilylation of B-2b and 3a In a nitrogen-filled glovebox, Ni(COD)(DQ) (0.0020 g, 0.0060 mmol, 0.050 equiv) and ITMe (0.0076 g, 0.0060 mmol, 0.050 equiv) were weighed directly into a 1-dram vial equipped with a stir bar. A stock solution of HSiPh3 (0.031 g, 0.12 mmol, 1.0 equiv added to each vial) was prepared in the corresponding solvent and distributed into each vial using a disposable 1-mL syringe. B-2b (17.5 µL, 0.12 mmol, 1.0 equiv) was added into the vial using a 25-µL syringe and the vial was sealed with a septum cap, brought out of the glovebox, and placed onto a preheated vial block at 100 °C. After 24 h, the reaction was quenched by cooling in a liquid N2 bath, opening 386 to air, and trimethoxybenzene (0.00298 g, 0.0177 mmol added to each vial) was added to the reaction as a stock solution using volumetric glassware in toluene via a 250-µL syringe. After mixing, an aliquot (10 µL) of the reaction was removed using a 25-µL syringe, filtered through Celite, and washed with CDCl3 directly into an NMR tube. The filtrate was analyzed by 1H NMR and 4a yield was determined by relative integration of the peak corresponding to 4a (t, 0.81 ppm, 3H) and the internal standard, trimethoxybenzene (s, 6.09 ppm, 3H). Selectivity was determined by GC-MS. Two trials were run for all experiments. Table D.8. Corresponding solvent and 1H NMR integrations of trimethoxybenzene and 4a, mmol of 4a, and % yield of 4a. Solvent ʃ Trimethoxybenzene ʃ4a Mmol 4a % Yield 4a 3.00 6.38 0.0377 Toluene 31.55±0.03% 3.00 6.37 0.0377 3.00 8.16 0.0483 Cyclohexane 40.9±0.8% 3.00 8.38 0.0496 3.00 7.82 0.0463 n-octane 43±6% 3.00 9.61 0.0568 3.00 4.07 0.0241 Hexanes 29±12% 3.00 7.57 0.0448 D.1.5. Remote Hydrosilylation In a nitrogen-filled glovebox, Ni(COD)(DQ) (0.0040 g, 0.012 mmol, 0.10 equiv), MeIPr and ITMe were weighed directly into a 1-dram scintillation vial equipped with a stir bar. To this vial was added toluene (0.60 mL), and a previously prepared stock solution of 3a (0.062 g, 0.24 mmol, 1.0 equiv) and cyclooctane (10 µL, 0.074 mmol) in toluene was distributed to obtain a total volume of 1.0 mL. The vial was sealed with a septum cap, removed from the glovebox, injected with 1b (36 µL, 0.24 mmol, 1.0 equiv) and placed on a preheated vial block at 80 °C. After 24 h, an aliquot (~20 µL) was removed using a 25-µL syringe, filtered into a GC-MS vial through Celite, and diluted with hexanes. The filtrate from the Celite plug was analyzed by GC or GC-MS to 387 assess the reaction progress and selectivity. The product concentration was determined by relative integration (by GC-MS) of the alkene against cyclooctane, in accordance with calibration curves. Two trials were run for all experiments. Table D.9. Reaction conditions of remote hydrosilylation reactions tested. % % MeIPr/ITMe Temperature Time conversion of conversion Selectivity Entry catalyst (° C) (h) 1b to A-2b of 1b to HS (4a/4b-4d) loading and B-2b products 1* 5:5 mol % 50 8.5 86±11% 0% n/a 5:5 mol % 100 24 80.4±0.4% 64.49±0.02% 3.1:1 2* 5:5 mol % 60 7.0 86±15% 0% n/a 5:5 mol % 100 24 77.5±0.4% 67.7±0.3% 4.2:1 3 5:5 mol % 100 21 80±2% n/a 5.0:1 4 2.5:7.5 mol % 100 24 75±3% n/a 3.8:1 5 5:5 mol % 90 24 63±8% 69±6% 10:1 *reactions were run using 10 mol % Ni(COD)2 in toluene. 388 APPENDIX E SUPPLEMENTARY CONTENT FOR CHAPTER VI Experimental details E.1.1. Materials and Methods All syntheses and manipulations were carried out under nitrogen using standard Schlenk (vacuum 10-2 mbar) techniques or in a nitrogen-filled glovebox unless otherwise indicated. All reagents and solvents were used after drying and stored under nitrogen, unless otherwise indicated. Tetrahydrofuran (THF; Fisher Chemical; HPLC grade, unstabilized), hexanes (Fisher Chemical; HPLC grade), diethyl ether (B&J Brand; HPLC grade, unstabilized), dimethylformamide (DMF; Fischer Chemical; ACS grade) were dispensed under nitrogen from an LC Technology SP-1 solvent system. C6D6 and CDCl3 were purchased from Cambridge Isotope Laboratories, degassed by freeze-pump-thaw, and thereafter stored on activated 4Å molecular sieves under nitrogen. All stock solutions were prepared by mass and were dispensed into the reaction vessel by difference from syringe, as detailed in the procedure for each experiment. The following reagents were used from commercial sources without further purification: Zirconium (IV) oxynitrate hydrate (ZrO(NO3)2•nH2O, we used the molecular weight for the hexahydrate form in all calculations,292 Sigma Aldrich), ammonium hydroxide (NH4OH; Fisher Scientific), sulfuric acid (H2SO4; Fisher Scientific), ferrocene (Acros), 2-allylphenol (1l, TCI), pyridine (Aldrich), tosyl chloride (TCI), sodium bicarbonate (NaHCO3; Fisher Scientific), 3- bromo-thiophene-2-carboxylic acid (Oakwood), allylbromide (TCI), methyl iodide (MeI, TCI), Potassium hexafluorophosphate (KPF6, Oakwood), magnesium turnings (Acros), iodine (Mallinckrodt), 1,4-dibromobenzene (Aldrich), silver nitrate (AgNO3; VWR), potassium tert- butoxide (KOt-Bu; Strem), phenylacetaldehyde (Alfa Aesar), nickel tetrakistriphenylphosphite (Ni[P(OPh)3]4, Sigma-Aldrich), Nickel tetrakistriphenylphosphine (Ni(PPh3)4, Acros), bis(1,5- cyclooctadiene)nickel(0) (Ni(cod)2, Strem), benzenethiol (Aldrich), 1,4-dichlorobenzene (Aldrich), bromobenzene (TCI), furan (TCI), acetophenone (Aldrich), benzaldehyde (Sigma- Aldrich), iodobenzene (Aldrich), phenylacetylene (TCI), aniline (Fischer Scientific), vinylacetic acid (Fischer Scientific), 3-sulfolene (1r, Sigma), 1-decene (1z, TCI), N-allylaniline (Acros), limonene (TCI), Tricyclohexylphosphine tetrafluoroborate (PCy3•BF4; Ambeed), 389 Bis(dibenzylideneacetone)palladium(0) (Pd(dba)2; Frontier Scientific), tri-tert-butylphosphine (P(t-Bu)3; Alfa Aesar), isobutyryl chloride (i-PrClCO; Thermo Scientific), styrene (TCI), bis(pinacolato)diboron (B2Pin2, Frontier Scientific), lithium tert-butoxide (LiOt-Bu, Alfa Aesar), diphenylsilane (Acros Organics), NafionTM and Amberlyst®-15 were used from commercial sources without further purification. The [H+] value (0.919 mmol/g) used for Nafion was the charge carrier density,293 which was determined according to a literature procedure. The [H+] value used for Amberlyst®-15 was (4.73 mmol/g).294 Procedure abbreviations: overnight (o.n.), Milli-Q water (MQ), chloroform (CHCl3), dichloromethane (DCM), magnesium sulfate (MgSO4), dimethylformamide (DMF), potassium carbonate (K2CO3), ethylacetate (EtOAc), methanol (MeOH), diethylether (Et2O), ethanol (EtOH), tetrahydrofuran (THF), sodium sulfite (Na2SO3), sodium sulfate (Na2SO4), 1,3-bis(2,6- diisopropylphenyl)imidazole-2-ylidene (IPr), 1,5-hexadiene (hex). Yields quantified by GC were determined using a calibration curve of the product against an internal standard (cyclooctane or durene). Conversions quantified by GC were determined by relative ratio(s) of the integrations of the starting material and product(s). At least two trials were run for all reactions, except for isolated yields, and the averages of these two trials are reported. The errors reported are the standard deviations of the two trials. The following compounds and materials were synthesized via reported procedures: Bn2Mg(THF) 295 2, 2-(3-buten-1-yl)pyridine, 296 CD PPh Br,2973 3 Ni[P(OEt)3]4, 298 (IPr)Ni(hex),230 1a,230 1b,230 1c,230 1d,230 1e,230 1f (in 3 steps),299–301 1h,230 1i,230 1j,230 1k,230 1m,230 1o,302 1p,303 1s,304 1t,230 1u,305 1v,306 1w,230 1x,307 1aa,230 N-allyl-N-phenylaniline,308 homoallylcarbonate (in two steps),309,310 4-penten-1-yn-1-ylbenzene,311 (1-cyclopropylethenyl)benzene,230 and (IPr) 3122Ni2Cl2. ZrO2-700 (0.072 mmol H +/g),313 SiO2-700 (0.29 mmol H +/g),314 and Al + 3152O3-700 (0.15 mmol H /g) were synthesized as previously reported. The [H+] for each of these solids was determined by titration with Bn2Mg(THF)2 (see section 3a below for analogous procedure with SZO300). E.1.2. General Experimental Nuclear magnetic resonance (NMR) spectra were collected at room temperature (298 K) unless otherwise stated on a Bruker Avance-III HD 500 NMR (499.90 MHz for 1H; 160.49 MHz for 11B; 126 MHz for 13C; 471 MHz for 19F; 99 MHz for 29Si). 1H and 13C spectra were referenced to the 390 residual solvent peak (CDCl3: 1H δ = 7.26 ppm, 13C δ = 77.16 ppm; C6D6: 1H δ = 7.16 ppm, 13C δ = 128.06 ppm. Chemical shifts for 1H, 13C, and 29Si NMR spectra are reported in parts per million (ppm, δ) relative to tetramethylsilane at 0.00 ppm. Peaks are characterized as follows: singlet (s), doublet (d), triplet (t), quartet (q), quintet (quint), multiplet (m), multiple signals (ms), broad (b), doublet of quartets (dq). Coupling constants, J, are reported in Hz. Infrared (IR) spectroscopy for air-stable organic compounds was performed on an Agilent Nicolet 6700 FT-IR using the ATR sampling technique. IR spectra for air-sensitive SZO300 was recorded as a self-supported pellet using a Bruker Alpha II FTIR spectrometer that is housed in a nitrogen-filled glovebox. All bands are reported in wavenumbers (cm-1) and are described as broad (br), strong (s), medium (m), and weak (w). For catalytic reactions, yields were determined using Gas Chromatography-Mass Spectrometry (GC-MS) or Gas Chromatography-Flame Ionization Detector (GC) against an internal standard. GC-MS was carried out on a Shimadzu GC-2010 Plus/GCMS-QP2010 SE using a Restek Rtx®- 5 (Crossbond 5% diphenyl – 95% dimethyl polysiloxane; 15 m, 0.25 mm ID, 0.25 μm df) column. GC was carried out on a Thermo Fisher Trace 1300 Gas Chromatograph using a Restek Rtx®-5 (Crossbond 5% diphenyl – 95% dimethyl polysiloxane; 15 m, 0.25 mm ID, 0.25 μm df) column. High-resolution mass spectrometry (HRMS) was carried out on a Waters XEVO G2-XS TOF mass spectrometer. E.1.3. Synthesis of Non-Commercial Reagents c. Preparation of SZO300 Sulfated zirconia (SZO300) was synthesized via a modified literature procedure:202 In a 1 L Erlenmeyer flask equipped with an overhead mechanical stirrer, ZrO(NO3)2•nH2O (70 g, 210 mmol, 1.0 equiv) and MQ water (420 mL) were added and heated to 65 °C in a sand bath until all solids dissolved. To this stirring solution, aqueous NH4OH (2.2 M, 280 mL, 620 mmol, 3.0 equiv) was added dropwise using an addition funnel over 2 h to form a white precipitate. Upon full addition of NH4OH, the pH of the white slurry was ~10, as measured using pH paper. The stirring 391 slurry was then heated to 95 °C for 24 h. The reaction was filtered while hot via vacuum filtration using a medium fritted funnel. The white precipitate was transferred into a beaker with MQ water (700 mL) and stirred. After 30 minutes, the solid was collected via vacuum filtration using a medium fritted funnel, washed with MQ water (3000 mL), transferred into a beaker and pressed down to make the solid more compact, and placed in an oven set at 110 °C overnight. The resulting compacted Zr(OH)4•nH2O was removed from the oven and allowed to cool to room temperature. The white solid was gently ground up using a motor and pestle and sieved to collected 250-425 µm-sized particles, yielding Zr(OH)4•nH2O as a white solid (13 g). Zr(OH)4•nH2O (5.0 g) was added to an aqueous solution of H2SO4 (0.50 M, 100 mL, 50 mmol) at room temperature, in which gas evolution was observed. After 30 min, the gas evolution had ceased, and the solution was poured away from the white solid. The solid was suspended in MQ water (100 mL). After 30 min, the water was decanted and the solid was dried for 1 h in the oven set at 110 °C. The solid, SZO, was removed from the oven and allowed to cool to room temperature. In a quartz flow reactor, 1.6 g of SZO was heated to 600 °C (ramp rate of 5 °C/min) under a flow of dry air (flow rate = 90-100 mL/min) and held at 600 °C for 4 h. The material was allowed to cool to room temperature for 9 h under a flow of dry air. SZO was then dehydroxylated by heating to 300 °C (ramp rate = 5 °C/min) under a flow of air (flow rate = 90-100 mL/min) for 3 h, and then the reactor was evacuated to 10-8 bar for 20 min at 300 °C to yield SZO300. The reactor was sealed while hot and under vacuum and was immediately transferred into a N2 glovebox, and SZO300, a white solid (1.5 g), was stored in the glovebox. The IR spectrum was recorded (Figure E.1.). 392 SZO300 3550 3050 2550 2050 1550 1050 550 Wavenumber (cm-1) Figure E.1. IR of SZO300. SZO300 titration: The concentration of acidic sites, [H+], was quantified by titration. SZO300 was weighed directly into an NMR tube. A stock solution of Bn2Mg(THF)2 and ferrocene (internal standard) in C6D6 was prepared using volumetric glassware and then distributed into the NMR tube with the acidic solid (amounts can be found in Table S1). A 1H NMR spectrum (8 scans, 60 s relaxation delay, Figure S2) was recorded as quickly as possible, since that resulted in the most reproducible and reliable results. The concentration of acidic sites was quantified by relative integrations between toluene’s methyl peak (singlet at 2.11 ppm, 3H) and ferrocene (singlet at 4.01 ppm, 10H). Titrations were run in duplicate, and the amounts and integrations of SZO300, ferrocene, Bn2Mg(THF)2, and toluene are shown below. The average concentration of H + found on SZO300 was 0.219 mmol H +/g for this batch. The concentration of H+ of the different SZO300 batches varied between 0.190-0.219 mmol H+/g, therefore an average of 0.200 mmol H+/g was used to determine the mmol and equivalents of H+ added to each reaction. 393 Figure E.2. 1H NMR spectrum of the titration of SZO300 with Bn2Mg(THF)2 in C6D6. Table E.1. Amounts added and integrations of peaks in the 1H NMR used to titrate the acidic solid to determine [H+]. SZO300 Ferrocene Bn2Mg(THF)2 mmol H +/g Trial ʃC7H8 ʃferrocene mass (mg) mass (mg) mass (mg) SZO300 1 10.1 10.0 15.8 0.13 10 0.225 2 10.4 10.0 15.8 0.12 10 0.213 Average 0.219 d. Synthesis of Starting Materials 4-methylbenzenesulfonate-2-(2-propenyl)-phenol (1x): 1l (1.0 mL, 7.7 mmol, 1.0 equiv) and CHCl3 (10 mL) were added to an oven-dried Schlenk flask equipped with a magnetic bar. The flask was cooled to 0 °C in an ice-water bath and pyridine (1.9 mL, 24 mmol, 3.1 equiv) was added followed by 394 tosyl chloride (small portions were added at a time, 2.9 g, 15 mmol, 2.0 equiv). The reaction warmed to room temperature and was left to stir for 48 h. The reaction was quenched with NaHCO3 (20 mL) and extracted with DCM (3 x 50 mL). The combined organic layers were dried over MgSO4, filtered, and the filtrate was concentrated under reduced pressure to obtain a yellow oil as the crude product. The crude product was purified by column chromatography (silica, 0:100 to 6:94 Et2O/hexanes) to yield 1x as a white, crystalline solid (0.886 g, 3.07 mmol, 40% yield). NMR spectra match values previously reported.316 IR (ATR, neat) v: 3081-2859 (w), 1485 (s), 1371 (s), 1177(s), 868 (s) 2-propen-1-yl-3-bromo-2-thiophenecarboxylate (1q): 3-bromo-thiophene-2-carboxylic acid (0.50 g, 2.4 mmol, 1.0 equiv) and DMF (6.0 mL) were added to a nitrogen-flushed, two-neck round-bottom flask equipped with a stir bar. Anhydrous K2CO3 (0.50 g, 3.6 mmol, 1.5 equiv) was added, and the reaction was stirred for 10 min at room temperature. Allylbromide (0.35 mL, 4.0 mmol, 1.7 equiv) was then added to this stirring solution. After 2 h, the reaction was quenched with water (5.0 mL) and extracted with EtOAc (3 x 10 mL). The combined organic phases were washed with water (10 mL) and brine (10 mL), dried over MgSO4, filtered, and the filtrate was concentrated under reduced pressure, giving a yellow oil as the crude product. The crude product was purified by column chromatography (silica, 0:100 to 10:90 EtOAc/hexanes) to yield 1q as a colorless oil (0.168 g, 0.680 mmol, 28% yield). 1H NMR (500 MHz, CDCl3, 298 K): δ 7.47 (d, J = 5.2 Hz, 1H), 7.10 (d, J = 5.2 Hz, 1H), 6.01 (ddt, J = 17.2, 10.5, 5.6 Hz, 1H), 5.43 (dq, J = 17.2, 1.4 Hz, 1H), 5.29 (dq, J = 10.5, 1.4 Hz, 1H), 4.81 (dt, J = 5.6, 1.3 Hz, 2H) 13C NMR (126 MHz, CDCl3, 298 K): δ 160.5, 133.1, 131.8, 131.5, 127.5, 118.7, 117.3, 65.9 IR (ATR, neat) v: 3102-2887 (w), 1720 (s), 1414 (s), 1229 (s), 1066 (s) ASAP/HRMS (m/z): [M+] calculated for C8H7BrO2S 245.9350, found 245.9334 395 2-(3-buten-1-yl)-1-methylpyridinium iodide (S1): 2-(3-buten-1-yl)pyridine (0.60 mL, 4.2 mmol, 1.0 equiv) (the density predicted by SciFinder was used: 0.927 g/mL), methyl iodide (1.3 mL, 21 mmol, 5.0 equiv), and MeOH (6.0 mL) were combined in a round bottom flask equipped with a stir bar. The reaction was stirred at room temperature for three days. The solvent was removed under reduced pressure and an orange, highly viscous oil was obtained. This oil was washed with Et2O (3 x 3 mL) and the crude product slowly turned into a pale-yellow solid. The crude product was purified by recrystallization in EtOH (4 mL) and Et2O (100 mL), giving S1 as pale-yellow crystals (0.257 g, 0.935 mmol, 22% yield). 1H NMR (500 MHz, CDCl3, 298 K): δ 9.43 (d, J = 6.1 Hz, 1H), 8.44 (td, J = 7.9, 0.9 Hz, 1H), 7.96 (t, J = 7.0 Hz, 1H), 7.90 (d, J = 8.2 Hz, 1H), 5.87 (ddt, J = 17.0, 10.3, 6.6 Hz, 1H), 5.16-5.09 (ms, 2H), 4.56 (s, 3H), 3.31 (t, J = 7.5 Hz, 2H), 2.61 (m, 2H) 13C NMR (126 MHz, CDCl3, 298 K): δ 158.1, 147.4, 145.4, 134.6, 128.6, 126.1, 118.2, 47.3, 32.8, 31.1 IR (ATR, neat) v: 3085-2845 (w), 1628 (s), 1509 (s), 1200 (s), 776 (s) ASAP/HRMS (m/z): [M+] calculated for C10H14IN 275.0171, found 275.0316 2-(3-buten-1-yl)-1-methylpyridinium hexafluorophosphate (S2): S1(0.66 g, 2.3 mmol, 1.0 equiv) was dissolved in a minimal amount of acetone (~10 mL) in a 4-dram vial equipped with a stir bar. Potassium hexafluorophosphate (0.41 g, 2.2 mmol, 1.0 equiv) was also dissolved in minimal amounts of acetone (~8 mL) in a separate vial, and then this solution was added to the stirring solution of S1. A white precipitate formed, and the reaction was stirred for 30 min at room temperature. The reaction was concentrated, and a yellow solid formed. This crude product was recrystallized in EtOH (~20 mL) at 0 °C, and the solid was collected via vacuum filtration and washed with cold EtOH (~5 mL), yielding S2 as a fluffy, white solid (0.306 g, 1.04 mmol, 45% yield). 1H NMR (500 MHz, (CD3)2CO, 298 K): δ 9.01 (d, J = 6.1 Hz, 1H), 8.58 (t, J= 7.9 Hz, 1H), 8.12 (d, J = 8.0 Hz, 1H), 8.01 (t, J = 6.9 Hz, 1H), 5.98 (ddt, J = 17.1, 10.3, 6.6 Hz, 1H), 5.18 (dq, J = 17.1, 1.5 Hz, 1H), 5.08 (qd, J = 10.3, 1.5 Hz, 1H), 4.52 (s, 3H), 3.39 (t, J = 7.5 Hz, 2H), 2.68 (q, J = 7.5 Hz, 2H) 396 13C{1H} NMR (126 MHz, (CD3)2CO, 298 K): δ 159.3, 147.6, 146.2, 136.6, 129.4, 126.4, 117.3, 46.4, 32.5, 31.5 31P{1H} NMR (202 MHz, (CD3)2CO, 298 K): δ -144.35 (sept, J = 707.0 Hz) 19F NMR (471 MHz, (CD3)2CO, 298 K): δ 72.23 (d, J = 707.5 Hz) IR (ATR, neat) v: 3106-2914 (w), 1634 (m), 1442 (m), 1188 (m), 814 (s) ASAP/HRMS (m/z): [M+] calculated for C10H14F6NP 293.0768, found 293.0672 1-Allyl-4-bromobenzene (1y): Magnesium turnings (0.36 g, 15 mmol, 1.8 equiv), iodine (single grain, catalytic amount), and THF (21 mL) were added to an oven-dried two-neck round bottom flask equipped with a stir bar. The mixture was stirred for 15 min, followed by gradual addition of 1,4- dibromobenzene (3.18 g, 13.5 mmol, 1.6 equiv) in several portions. The flask was equipped with a nitrogen-flushed condenser and heated to reflux in an oil bath. After 1 h the flask was removed from the oil bath and cooled to 0 °C in an ice-water bath. After stirring for 15 min, allyl bromide (1.4 mL, 8.3 mmol, 1.0 equiv) was added dropwise to the reaction mixture. The reaction was warmed to room temperature and left stirring for 4 h. The solution was then quenched with saturated NH4Cl solution (20 mL) and extracted with Et2O (3 x 30 mL). The combined organic layers were washed with saturated Na2SO3 solution (20 mL), dried over Na2SO4, and filtered. The filtrate was concentrated under reduced pressure to obtain a yellow oil as the crude product. The crude product was purified by column chromatography (10% AgNO3 impregnated silica, 100% hexanes followed by an additional silica column 100% hexanes) to yield 1y as a yellow oil (1.04 g, 5.3 mmol, 39% yield). NMR spectra match values previously reported.317 4-Allyl-benzaldehyde (1g): Magnesium turnings (0.14 g, 5.8 mmol, 1.1 equiv), iodine (single grain, catalytic amount), and THF (10 mL) were added to an oven-dried Schlenk flask equipped with a stir bar. The mixture was stirred for 15 min, followed by gradual addition of 1y (1.0 g, 5.1 mmol, 1.0 equiv) 397 in several portions. The flask was equipped with a nitrogen-flushed condenser and heated to reflux in an oil bath. After 2 h the flask was removed from the oil bath and cooled to 0 °C in an ice-water bath. After stirring for 15 min, DMF (0.85 mL, 11 mmol, 2.2 equiv) was added dropwise to the reaction mixture. The reaction was warmed to room temperature and left stirring for 2 h. The solution then was quenched with saturated NH4Cl solution (10 mL) and extracted with Et2O (3 x 15 mL). The combined organic layers were dried over Na2SO4 and filtered. The filtrate was concentrated under reduced pressure to obtain a yellow oil as the crude product. The crude product was purified by column chromatography (silica, 30:70 Et2O/hexanes) to yield 1g as a colorless oil (0.26 g, 1.8 mmol, 35% yield). NMR spectra match values previously reported.317 Allybenzene-dn (1c-dn) was synthesized via modified literature procedure: 230 CD3PPh3Br (4.0 g, 11 mmol, 1.2 equiv) and THF (60 mL) were added to a nitrogen-flushed, oven-dried Schlenk flask equipped with a stir bar and cooled to 0 °C in an ice-water bath. To this stirring solution was added KOt-Bu (1.2 g, 11 mmol, 1.2 equiv) and the reaction turned a bright yellow color. The reaction was stirred for 1 h at 0 °C before phenylacetaldehyde (1.0 mL, 9.0 mmol, 1.0 equiv) was added dropwise with a disposable 3-mL syringe, turning the reaction a bright orange color. The reaction was stirred at 0 °C for 3 h before warming it to room temperature and allowing it to stir overnight. The following day, the reaction was opened to air and quenched with water (50 mL). The organic layer was separated, and the aqueous layer was extracted with Et2O (3 x 50 mL). The combined organic layers were dried over MgSO4, filtered, and the filtrate was concentrated under reduced pressure to obtain a crude yellow oil. The crude product was purified by column chromatography (silica, 100% pentane) to yield 1c-dn as a colorless oil (0.092 g, 0.77 mmol, 9% yield). E.1.4. Evaluation of Reaction Conditions for Isomerization 398 Homogeneous catalyst: In a nitrogen-filled glovebox, a stock solution of the Ni complex (0.0036 mmol, 0.030 equiv added to the vial) and cyclooctane (internal standard; 8.0 μL, 0.060 mmol added to the vial) in the reaction solvent was prepared; the appropriate amount was then added to a vial equipped with a stir bar using a 1-mL plastic syringe. The vial was sealed with a septum cap and brought out of the glovebox. A stock solution of H2SO4 (H +) was prepared (0.0036 mmol, 0.030 equiv H2SO4) in the reaction solvent and the appropriate amount was injected into the vial using a 1-mL plastic syringe. The total volume of solvent used in the reaction was 2.0 mL. The vial was then injected with 1a (18.5 μL, 0.120 mmol, 1 equiv) using a 25-µL syringe, heated to 30 °C on a preheated aluminum vial block, and stirred at a rate of 150 rpm. After one hour, an aliquot (~20 µL) was removed using a 25-µL syringe, diluted with hexane, and filtered through a Celite plug into a GC vial. The filtrate was analyzed by GC to assess the progress and selectivity of the reaction. Heterogeneous catalyst: In a nitrogen-filled glovebox, the solid acid source (H+; 0.00018-0.006 mmol H+, 0.003-0.10 equiv H+ added to the vial) was weighed directly into a 4-dram scintillation vial equipped with a stir bar. A stock solution of the Ni complex (0.0006-0.006 mmol, 0.01-0.10 equiv added to the vial) and cyclooctane (internal standard; 4.0 μL, 0.030 mmol added to the vial) in the reaction solvent was prepared; the appropriate amount was then added to the solid acid using a 1-mL plastic syringe. The total volume of solvent used in the reaction was 1.0 mL. The vial was sealed with a septum cap and brought out of the glovebox. The vial was then injected with 1a (9.5 μL, 0.062 mmol, 1.0 equiv) using a 25-µL syringe, heated to 30 °C on a preheated aluminum vial block, and stirred at a rate of 150 rpm. After one hour, an aliquot (~20 µL) was removed using a 25-µL syringe, diluted with hexane, and filtered through a Celite plug into a GC vial. The filtrate was analyzed by GC to assess the progress and selectivity of the reaction. Results from optimization screening reactions are summarized below in Table E.2. Table E.2. Optimization of the isomerization of allylanisole 1a to anethole 2a. Ni complex Acid source Entry + solvent Yield (%) E/Z (mol %) (mol % H ) 1 Ni[P(OEt)3]4 (3) H2SO4 (3) MeOH 92 ± 8 34 : 1 2 Ni[P(OEt)3]4 (3) H2SO4 (3) Et2O 86 ± 1 17 : 1 3 Ni[P(OEt)3]4 (3) SZO300 (3) Et2O 78 ± 3 17 : 1 4 Ni[P(OEt)3]4 (3) ZrO2-700 (3) Et2O 0 — — 5 Ni[P(OEt)3]4 (3) Al2O3-700 (3) Et2O 0 — — 399 6 Ni[P(OEt)3]4 (3) SiO2-700 (3) Et2O 0 — — 7a Ni[P(OEt)3]4 (3) Nafion TM (5) Et2O 10 ± 3 15 : 1 8a Ni[P(OEt)3]4 (3) Amberlyst®-15 (5) Et2O 20 ± 3 11 : 1 9 Ni[P(OPh)3]4 (3) SZO300 (3) Et2O 0.2046 ± 0.0007 1 : 0 10 Ni(PPh3)4 (3) SZO300 (3) Et2O 3.1 ± 0.3 5 : 1 11 Ni(cod)2 (3) SZO300 (3) Et2O 0.5 ± 0.2 1 : 0 12 (IPr)Ni(hex) (3) SZO300 (3) Et2O 0.5 ± 0.2 1 : 0 13 Ni[P(OEt)3]4 (3) SZO300 (3) THF 46 ± 2 7 : 1 14 Ni[P(OEt)3]4 (3) SZO300 (3) Toluene 19 ± 5 12 : 1 15 Ni[P(OEt)3]4 (3) SZO300 (3) Hexanes 36.4 ± 0.2 11 : 1 16 None --- SZO300 (3) Et2O 0 — — 17 Ni[P(OEt)3]4 (3) None --- Et2O 0.5 ± 0.1 1 — 18 Ni[P(OEt)3]4 (3) SZO300 (0.3) Et2O 37 ± 9 8 : 1 19 Ni[P(OEt)3]4 (3) SZO300 (1) Et2O 48 ± 5 10 : 1 20 Ni[P(OEt)3]4 (3) SZO300 (2) Et2O 68 ± 9 11 : 1 21 Ni[P(OEt)3]4 (3) SZO300 (5) Et2O 83 ± 1 22 : 1 22 Ni[P(OEt)3]4 (3) SZO300 (10) Et2O 72 ± 3 31 : 1 23 Ni[P(OEt)3]4 (1) SZO300 (1) Et2O 27 ± 4 13 : 1 24 Ni[P(OEt)3]4 (5) SZO300 (5) Et2O 79 ± 1 27 : 1 25 Ni[P(OEt)3]4 (10) SZO300 (10) Et2O 82 ± 2 28 : 1 a0.12 mmol 1a scale E.1.5. Additive Screening and Their Effect on Isomerization In a nitrogen-filled glovebox, SZO300 (15 mg, 0.0030 mmol H +, 0.050 equiv H+ per vial) was weighed directly into a 1-dram vial equipped with a stir bar. A stock solution of Ni[P(OEt)3]4 in Et2O was prepared and the appropriate amount was distributed to the vial using a disposable 1-mL syringe (1.3 mg, 0.0018 mmol, 0.030 equiv was added to each vial). To each vial was added cyclooctane (internal standard; 5.0 µL, 0.037 mmol) using a 25-µL syringe. The total volume of Et2O in the vial was 1.0 mL. The vial was sealed with a septum cap and brought out of the glovebox. The corresponding additive (0.060 mmol, 1.0 equiv) was added to the vial using a 10- µL syringe followed by 1c (8.0 uL, 0.060 mmol, 1.0 equiv) using a 25-µL syringe. The reaction was then immediately heated to 30 °C using a preheated aluminum block and stirred at a rate of 150 rpm. The reaction progress was monitored by GC by taking aliquots (~20 µL) over time. The aliquots were diluted with hexanes (1 mL) and filtered through Celite into a GC vial. Two trials 400 were run for each experiment, and the yield averages and standard deviations are reported in Table S3 below. Table E.3. Additive, reaction time, yield of 2c, and E/Z selectivity for the additive screening experiments. E/Z Selectivity Entry Additive Time (h) Yield 2c (%) (std error) 1 5 96±2 35.6:1 (0.7) 2 2 97.0±0.6 35:1 (1) 3 1 97±3 33.82:1 (0.05) 4 1 95±2 32.0:1 (0.7) 5 1 99±3 32.4:1 (0.9) 6 5 94±9 29:1 (3) 7 5 34±2 ..3.948:1 (0.008) 8 5 0.5±0.1 1:0… 9 5 7±1 ..1.83:1 (0.02) E.1.6. Evaluation of the Substrate Scope for Isomerization a. General Procedure for the Isomerization and Isolation of Products General Procedure: In a nitrogen-filled glovebox, Ni[P(OEt)3]4 (21.7 mg, 0.0300 mmol, 0.0300 equiv), SZO300 (250 mg, 0.0500 mmol H +, 0.0500 equiv H+), and Et2O (17 mL) were added to a 4-dram scintillation vial equipped with a stir bar. The vial was sealed with a septum cap, brought out of the glovebox, injected with the alkene (1.00 mmol, 1.00 equiv) using a 250-µL syringe, and heated at 30 °C on a preheated aluminum vial block for an allotted amount of time specified below for each alkene. The reaction was stirred at a rate of 150 rpm. The reaction progress was monitored 401 by GC or GC-MS by taking aliquots (~5 µL) over time; the aliquots were diluted with hexanes (1 mL) and filtered through Celite into a GC vial. When the reaction was complete, it was removed from heat, opened to air, and the solution was filtered through Celite, washing Et2O (2.0 mL). The filtrate was concentrated, and the product was purified as described below for each substrate. b. General Procedure for the Isomerization and Isolation of Products Anethole (2a) Synthesis details: substrate 1a, 30 °C, crude E/Z ratio determined by GC = 34:1 (E/Z) Reaction time: 6 h Purification details: column chromatography: silica, 0:100 to 5:95 Et2O/hexanes gradient to give the product as a colorless oil (0.114 g, 0.769 mmol, 77% yield). NMR spectra match values previously reported.228,318 The major product isolated is the E-isomer, and the Z-isomer is seen in the NMR spectra as well. The ratio of these isomers determined by the integration of H in the β-position was found to be 32:1 (E/Z). E-isomer: 1H NMR (500 MHz, C6D6, 298 K): δ 7.20 (d, J = 8.7 Hz, 2H), 6.77 (d, J = 8.7 Hz, 2H), 6.32 (dq, J = 15.7, 1.8 Hz, 1H), 5.96 (dq, J = 15.7, 6.6 Hz, 1H), 3.31 (s, 3H), 1.70 (dd, J = 6.6, 1.7 Hz, 3H) 13C{1H} NMR (126 MHz, C6D6, 298 K): δ 159.3, 131.25, 131.21, 127.4, 123.1, 114.3, 54.8, 18.5 1-(4-methylphenyl)-1-propene (2b) Synthesis details: substrate 1b, 30 °C, crude E/Z ratio determined by GC- MS = 36:1 (E/Z) Reaction Time: 3 h Purification details: pipette plug: silica, 5:95; Et2O/hexane to give the product as a colorless oil (0.123 g, 0.930 mmol, 93% yield). NMR spectra match values previously reported.318,319 402 The major product isolated is the E-isomer, and the Z-isomer is seen in the NMR spectra as well. The ratio of these isomers determined by integration of H in the β-position was found to be 34:1 (E/Z). E-isomer: 1H NMR (500 MHz, CDCl3, 298 K): δ 7.20 (d, J = 8.1 Hz, 2H), 7.07 (d, J = 8.1 Hz, 2H), 6.35 (dd, J = 15.7, 1.3 Hz, 1H), 6.15 (dq, J = 15.7, 6.6 Hz, 1H), 2.29 (s, 3H), 1.84 (dd, J = 6.6, 1.6 Hz, 3H) 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 136.5, 135.3, 131.0, 129.3, 125.8, 124.7, 21.2, 18.5 β-methylstyrene (2c) Synthesis details: substrate 1c, 30 °C, crude E/Z ratio determined by GC = 35:1(E/Z) Reaction Time: 3 h Purification details: pipette plug: silica, hexane to give the product as a colorless oil (0.111 g, 0.942 mmol, 94% yield). NMR spectra match values previously reported.318 The major product isolated is the E-isomer, and the Z-isomer is seen in the NMR spectra as well. The ratio of these isomers determined by the integration of H in the β-position was found to be 50:1 (E/Z). E-isomer: 1H NMR (500 MHz, C6D6, 298 K): δ 7.24 (d, J = 7.4 Hz, 2H), 7.14 (m, 2H), 7.05 (tt, J = 7.3, 1.4 Hz, 1H), 6.30 (dq, J = 15.7, 1.7 Hz, 1H), 6.03 (dq, J = 15.7, 6.6 Hz, 1H), 1.65 (dd, J = 6.6, 1.7 Hz, 3H) 13C{1H} NMR (126 MHz, C6D6, 298 K): δ 138.4, 131.7, 128.8, 127.1, 126.3, 125.5, 18.5 1-fluoro-3-(1-propen-1-yl)benzene (2d) Synthesis details: substrate 1d, 30 °C, crude E/Z ratio determined by GC- MS = 35:1 (E/Z) Reaction time: 3 h 403 Purification details: pipette plug: silica, 100% hexane to give the product as a colorless oil (0.123 g, 0.903 mmol, 90% yield). NMR spectra match values previously reported.230 The major product isolated is the E-isomer, and the Z-isomer is seen in the NMR spectra as well. The ratio of these isomers determined by integration of H in the β-position was found to be 25:1 (E/Z). E-isomer: 1H NMR (500 MHz, C6D6, 298 K): δ 6.96 (m, 1H), 6.89 (td, J = 7.8, 5.8 Hz, 1H), 6.85-6.83 (m, 1H), 6.71 (m, 1H), 6.10 (d, J = 15.8 Hz, 1H), 5.88 (dq, J = 15.7, 6.6 Hz, 1H), 1.56 (dd, J = 6.7, 1.7 Hz, 3H) 13C{1H} NMR (126 MHz, C6D6, 298 K): δ 163.8 (d, J = 244.7 Hz), 140.9 (d, J = 7.8 Hz), 130.5 (d, J = 2.5 Hz), 130.2 (d, J = 8.3 Hz), 127.1, 122.1 (d, J = 2.8 Hz), 113.8 (d, J = 21.5 Hz), 112.7 (d, J = 21.7 Hz), 18.3 19F NMR (471 MHz, C6D6, 298 zK): δ -113.72 (m) 1-(4-trifluoromethylphenyl)-1-propene (2e) Synthesis details: substrate 1e, 30 °C, crude E/Z ratio determined by GC = 43:1 (E/Z) Reaction Time: 2 h Purification details: pipette plug: silica, 100% pentane to give the product as a white solid (0.154 g, 0.828 mmol, 83% yield). NMR spectra match values previously reported.228 The major product isolated is the E-isomer, and the Z-isomer is seen in the 19F NMR spectrum as well. The ratio of these isomers determined by integration of F in the CF3 group and was found to be 33:1 (E/Z). E-isomer: 1H NMR (500 MHz, CDCl3, 298 K): δ 7.53 (d, J = 8.2 Hz, 2H), 7.41 (d, J = 8.2 Hz, 2H), 6.43 (d, J = 15.8 Hz, 1H), 6.34 (dq, J = 15.8, 6.4 Hz, 1H), 1.91 (d, J = 6.4 Hz, 3H) 404 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 141.5, 130.1, 128.8, 128.7 (q, J = 32 Hz), 125.6 (q, J = 3.8 Hz), 124.5 (q, J = 272 Hz), 18.7 19F NMR (471 MHz, CDCl3, 298 K): δ -62.39 Isosafrole (2f) Synthesis details: substrate 1f, 30 °C, crude E/Z ratio determined by GC = 38:1 (E/Z) Reaction time: 5 h Purification details: pipette plug: silica, 100% pentane to give the product as a colorless oil (0.142 g, 0.874 mmol, 87% yield). NMR spectra match values previously reported.228 The major product isolated is the E-isomer, and the Z-isomer is seen in the NMR spectra as well. The ratio of these isomers determined by integration of H in the allyl-methyl position was found to be 31:1 (E/Z). 1H NMR (500 MHz, C6D6, 298 K): δ 6.89 (s, 1H), 6.62 (s, 2H), 6.20 (dq, J = 15.7, 1.7 Hz, 1H), 5.83 (dq, J = 15.7, 6.7 Hz, 1H), 5.31 (s, 2H), 1.62 (dd, J = 6.7, 1.7 Hz, 3H) 13C{1H} NMR (126 MHz, C6D6, 298 K): δ 148.6, 147.2, 133.0, 131.2, 123.7, 120.6, 108.5, 105.8, 100.9, 18.3 IR (ATR, neat) v: 3069-2774 (w), 1488 (s), 1245 (s), 1038 (s), 935 (w) 4-(1-propen-1-yl)benzaldehyde (2g) Synthesis details: substrate 1g, 30 °C, crude E/Z ratio determined by GC- MS = 57:1 Reaction time: 5 h Purification details: column chromatography, silica, 0:100 to 5:95 Et2O/pentane to give the product as a pale yellow oil (0.138 g, 0.941 mmol, 94% yield). 1H NMR (500 MHz, C6D6, 298 K): δ 9.70 (s, 1H), 7.54 (d, J = 8.2 Hz, 2H), 7.05 (d, J = 8.2 Hz, 2H), 6.11 (dq, J = 15.8, 1.7 Hz, 1H), 5.96 (dq, J = 15.8, 6.6 Hz, 1H), 1.57 (dd, J = 6.6, 1.5 Hz, 3H) 405 13C{1H} NMR (126 MHz, C6D6, 298 K): δ 190.7, 143.7, 135.7, 130.7, 130.1, 129.3, 126.4, 18.5 IR (ATR, neat) v: 3023-2725 (w), 1687 (s), 1600 (s), 1212 (s), 964 (m) ASAP/HRMS (m/z): [M+] calculated for C10H10O 146.0732, found 146.0678 1-(2-methylphenyl)-1-propene (2h) Synthesis details: substrate 1h, 30 °C, crude E/Z ratio determined by GC = 12:1 (E/Z) Purification details: pipette plug: silica, 100% pentane to give the product as a colorless oil (0.128 g, 0.968 mmol, 97% yield). NMR spectra match values previously reported.318,319 The major product isolated is the E-isomer, and the Z-isomer is seen in the NMR spectra as well. The ratio of these isomers determined by integration of H in the β-position was found to be 13:1 (E/Z). The E-product is fully characterized below, and the peaks visible and clearly assignable to the Z- isomer are given directly following the NMR characterization of the E- product. Reaction time: 4 h E-isomer 1H NMR (500 MHz, C6D6, 298 K): δ 7.40 (dd, J = 7.4, 0.9 Hz, 1H), 7.06- 7.10 (m, 1H), 7.05 (td, J = 7.3, 1.4 Hz, 1H), 7.01 (m, 1H), 6.56 (qd, J = 15.6, 1.7 Hz, 1H), 5.96 (dq, J = 15.6, 6.6 Hz, 1H), 2.15 (s, 3H), 1.69 (dd, J = 6.6, 1.7 Hz, 3H) 13C{1H} NMR (126 MHz, C6D6, 298 K): δ 137.5, 134.9, 130.5, 129.6, 127.16, 126.83, 126.4, 126.0, 19.8, 18.8 Z-isomer: 1H NMR (500 MHz, C6D6, 298 K): δ 7.22 (m, 0.09H), 6.43 (qd, J = 11.4, 6.0 Hz, 0.08H), 5.69 (dq, J = 11.4, 6.9 Hz, 0.08H), 2.12 (s, 0.25H), 1.61 (dd, J = 7.0, 1.8 Hz, 0.24H) 406 13C{1H} NMR (126 MHz, C6D6, 298 K): δ 136.9, 136.4, 130.2, 129.52, 129.48 127.18, 126.81, 125.7, 19.9, 14.4 α,β-dimethylstyrene (2i) Synthesis details: 0.895 mmol substrate 1i, 3.4 mol % Ni[P(OEt)3]4, 5.6 mol % SZO300, 50 °C, crude E/Z ratio determined by GC = 5.5:1 (E/Z) Reaction time: 24 h Purification details: pipette plug: silica, 100% pentane to give the product as a colorless oil. 0.118 g was isolated with 2.6% 1i. The amount and yield of 2i was adjusted to 0.115 g, 0.870 mmol, 97% yield. NMR spectra match previously reported values.320 The major product isolated is the E-isomer, and the Z-isomer is seen in the NMR spectra as well. The ratio of these isomers determined by integration of H in the β-position was found to be 7.7:1 (E/Z) and 2.6% 1i Is seen. The E-isomer is fully characterized below, and the peaks visible and clearly assignable to the Z-isomer are given directly following the NMR characterization of the E-isomer. E-isomer: 1H NMR (500 MHz, CDCl3, 298 K): δ 7.36 (d, J = 7.5 Hz, 2H), 7.29 (t, J = 7.5 Hz, 2H), 7.20 (t, J = 7.0, 1H), 5.86 (qq, J = 6.4, 1.2 Hz, 1H), 2.02 (s, 3H), 1.79 (dq, J = 6.9, 1.1 Hz, 3H) 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 144.2, 135.7, 128.3, 126.53, 125.7, 122.6, 15.6, 14.5 Z-isomer: 1H NMR (500 MHz, CDCl3, 298 K): δ 5.56 (qq, J = 6.9, 1.2 Hz, 0.13H), 1.59 (dq, J = 3.4 Hz, 1.3 Hz, 0.39 H) 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 142.0, 137.0, 128.21, 128.16, 126.51, 121.7, 25.5, 15.0 1-(methoxymethoxy)-2-(1E)-1-propen-1-ylbenzene (2j) 407 Synthesis details: substrate 1j, 30 °C, crude E/Z ratio determined by GC = 19:1 Reaction time: 8 h Purification details: column chromatography: silica, 100% pentane to give the product as a colorless oil (0.121 g, 0.681 mmol, 68% yield). NMR spectra match values previously reported.321 The major product isolated is the E-isomer, and the Z-isomer is seen in the NMR spectra as well. The ratio of these isomers determined by integration of H in the β-position was found to be 19:1 (E/Z). The E-isomer is fully characterized below, and the peaks visible and clearly assignable to the Z- isomer are given directly following the NMR characterization of the E- isomer. E-isomer: 1H NMR (500 MHz, C6D6, 298 K): δ 7.42 (dd, J = 7.7, 1.6 Hz, 1H), 7.11 (dd, J = 8.3, 1.0 Hz, 1H), 7.04-6.99 (ms, 2H), 6.15 (qd, J = 15.8, 6.6 Hz, 1H), 4.87 (s, 2H), 3.12 (s, 3H), 1.75 (dd, J = 6.6, 1.7 Hz, 3H) 13C{1H} NMR (126 MHz, C6D6, 298 K): δ 154.7, 128.1, 126.7, 126.5, 126.2, 122.2, 115.2, 94.8, 55.6, 18.9 (one signal overlaps with C6D6 signal) 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 154.0, 128.0, 127.9, 126.7, 126.5, 125.7, 122.1, 115.0, 95.0, 56.2, 19.1 1-propen-1-yl-2-[(trimethylsilyl)oxy]benzene (2k) Synthesis details: substrate 1k, 30 °C, crude E/Z ratio determined by GC- MS = 28:1 (E/Z) Reaction time: 5 h Purification details: column chromatography: silica, 100% hexanes to give the product as a colorless oil (0.192 g, 0.930 mmol, 93% yield). NMR spectra match values previously reported.322 408 The major product isolated is the E-isomer, and the Z-isomer is seen in the NMR spectra as well. The ratio of these isomers determined by integration of H in the β-position was found to be 18:1 (E/Z). The E-product is fully characterized below, and the peaks visible and clearly assignable to the Z- isomer are given directly following the NMR characterization of the E- product. E-isomer: 1H NMR (500 MHz, C6D6, 298 K): δ 7.44 (dd, J = 7.7, 1.4 Hz, 1H), 7.00 (td, J = 7.7, 1.7 Hz, 1H), 6.92-6.86 (ms, 2H), 6.81 (dd, J = 8.0, 0.8 Hz, 1H), 6.13 (dq, J = 15.9, 6.6 Hz, 1H), 1.74 (dd, J = 6.6, 1.8 Hz, 3H), 0.17 (s, 9H) 13C{1H} NMR (126 MHz, C6D6, 298 K): δ 152.8 130.0, 128.0, 127.0, 126.9, 125.8, 122.1, 120.2, 18.9, 0.4 29Si{1H} NMR (99 MHz, C6D6, 298 K): 18.84 Z-isomer 1H NMR (500 MHz, C6D6, 298 K): δ 7.32 (dd, J = 7.5, 1.3 Hz, 0.07H), 7.04 (m, 0.08H), 6.84 (m, 0.09), 5.73 (dq, J = 11.6, 7.1 Hz, 0.06H), 1.72 (d, J = 1.8 Hz, 0.10H), 0.15 (s, 0.48H) 13C{1H} NMR (126 MHz, C6D6, 298 K): δ 153.7, 130.9, 126.6, 121.4, 120.1, 14.7 IR (ATR, neat) v: 3065-2853 (w), 1483 (m), 1248 (s), 911 (s), 840 (s) ASAP/HRMS (m/z): [M+] calculated for C12H18OSi 206.1127, found 206.1101 2-(1-propenyl)phenol (2l) Synthesis details: substrate 1l, 30 °C, crude E/Z ratio determined by GC- MS = 46:1 (E/Z) Reaction time: 4 h Purification details: column chromatography: silica, 0:100 to 5:95 gradient Et2O/pentane to give the product as a white solid (0.132 g, 0.984 mmol, 98% yield). NMR spectra match values previously reported.323 409 1H NMR (500 MHz, CDCl3, 298 K): δ 7.32 (dd, J = 7.7, 1.4 Hz, 1H), 7.11 (td, J = 7.7, 1.6 Hz, 1H), 6.90 (td, J = 7.5, 0.9 Hz, 1H), 6.80 (dd, J = 8.1, 0.9 Hz, 1H), 6.60 (dq, J = 15.8, 1.8 Hz, 1H), 6.23 (dq, J = 15.8, 6.6 Hz, 1H), 5.06 (s, 1H), 1.93 (dd, J = 6.6, 1.7 Hz, 3H) 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 152.4, 128.5, 128.1, 127.5, 125.4, 125.2, 121.0, 115.8, 19.0 {2-[(1E)-1-propen-1-yl]phenoxy}acetonitrile (2m) Synthesis details: 1.01 mmol of substrate 1m was used, 30 °C, crude E/Z ratio determined by GC = 26:1 (E/Z) Reaction time: 4 h Purification details: column chromatography: silica, gradient 0:100 to 3:97 gradient EtOAc/hexanes to give the product as a colorless oil (0.173 g, 0.996 mmol, 98% yield). NMR spectra match values previously reported.324 The major product isolated is the E-isomer, and the Z-isomer is seen in the NMR spectra as well. The ratio of these isomers determined by integration of H in the β-position was found to be 25:1 (E/Z). 1H NMR (500 MHz, C6D6, 298 K): δ 7.30 (dd, J = 7.7, 1.6 Hz, 1H), 6.90 (td, J = 7.8, 1.6 Hz, 1H), 6.82 (t, J = 7.5 Hz, 1H), 6.73 (dq, J = 15.9, 1.9 Hz, 1H), 6.41 (d, J = 8.2 Hz, 1H), 6.04 (dq, J = 15.9, 6.7 Hz, 1H), 3.57 (d, J = 1.0 Hz, 2H), 1.68 (dd, J = 6.7, 1.9 Hz, 3H) 13C{1H} NMR (126 MHz, C6D6, 298 K): δ 153.7, 128.5, 128.0, 127.6, 127.2, 125.3, 123.2, 115.4, 113.0, 53.4, 18.9 Crotonic acid (2n) Synthesis details: substrate 1n, 30 °C, only the E-isomer was observed by GC Reaction time: 5 h Purification details: column chromatography: silica, gradient 0:100 to 16:84 gradient Et2O/hexanes to give the product as a crystalline white solid 410 (0.0639 g, 0.742 mmol, 74% yield). NMR spectra match previously reported values.325 1H NMR (500 MHz, CDCl3, 298 K): δ 11.37 (br s, 1H), 7.10 (dq, J = 15.5, 7.0 Hz, 1H), 5.86 (dq, J = 15.5, 1.7 Hz, 1H), 1.92 (dd, J = 7.0, 1.7 Hz, 3H). 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 171.4, 147.6, 122.2, 18.3 IR (ATR, neat) v: 2976-2517 (br), 1683 (s), 1420 (m), 1222 (m), 965 (s) ASAP/HRMS (m/z): [M+] calculated for C5H8O 86.0368, found 86.0539 1-propen-1-yl-1H-indole (2o) Synthesis details: substrate 1o, 30 °C, crude E/Z ratio determined by GC = 8.5:1 (E/Z) Reaction Time: 8 h Purification details: column chromatography: silica, 0:100-3:97 EtOAc/hexanes to yield the product as a white solid (0.110 g, 0.700 mmol, 70% yield). NMR spectra match values previously reported.326 The major product isolated is the E-isomer, and the Z-isomer is seen in the NMR spectra as well. The ratio of these isomers determined by integration of H in the β-position was found to be 9.5:1 (E/Z). The E-isomer is fully characterized below, and the peaks visible and clearly assignable to the Z- isomer are given directly following the NMR characterization of the E- isomer. E-isomer: 1H NMR (500 MHz, C6D6, 298 K): δ 7.65-7.63 (m, 1H), 7.24-7.17 (ms, 3H), 7.01 (d, J = 3.3 Hz, 1H), 6.60 (dq, J = 14.0, 1.7 Hz, 1H), 6.52 (d, J = 3.3 Hz, 1H), 5.29 (dq, J = 14.0, 6.9 Hz, 1H), 1.49 (dd, J = 6.7, 1.7 Hz, 3H) 13C{1H} NMR (126 MHz, C6D6, 298 K): δ 135.9, 129.6, 125.1, 124.3, 122.7, 121.5, 120.8, 110.2, 109.9, 104.3, 15.1 Z-isomer: 411 1H NMR (500 MHz, C6D6, 298 K): δ 7.68 (m, 0.11H), 6.95 (d, J = 3.3 Hz, 0.09H), 6.54 (d, J = 3.3 Hz, 0.11H), 6.42 (dq, J = 8.5, 1.7 Hz, 0.11H), 5.05 (dq, J = 8.4, 7.2 Hz, 0.11H), 1.42 (dd, J = 7.1, 1.8 Hz, 0.31H) 13C{1H} NMR (126 MHz, C6D6, 298 K): δ 127.4, 124.8, 122.6, 121.3, 117.7, 110.5, 103.5, 12.8 2-(1-propenyl)-thiophene (2p) Synthesis details: 0.68 mmol substrate 1p, 4.4 mol % Ni[P(OEt)3]4, 7.4 mol % SZO300, 1 50 °C, crude E/Z ratio determined by H NMR = 6.3:1 (E/Z) Reaction time: 24 h Purification details: pipette plug: silica, 100% pentane to give the product as a colorless oil (0.0739 g, 0.878 mmol, 88% yield). NMR spectra values match previously reported.327,328 The major product isolated is the E-isomer, and the Z-isomer is seen in the NMR spectra as well. The ratio of these isomers determined by integration of H in the β-position was found to be 7.4:1 (E/Z). The E-isomer is fully characterized below, and the peaks visible and clearly assignable to the Z- isomer are given directly following the NMR characterization of the E- isomer. E-isomer 1H NMR (500 MHz, C6D6, 298 K): δ 6.73 (d, J = 5.0 Hz, 1H), 6.70-6.67 (ms, 2H), 6.34 (dq, J = 15.6, 1.7 Hz, 1H), 5.94 (qd, J = 15.6, 6.7 Hz, 1H), 1.54 (dd, J = 6.7, 1.7 Hz, 3H) 13C{1H} NMR (126 MHz, C6D6, 298 K): δ 143.5, 127.4, 125.5, 124.9, 124.4, 123.2, 18.2 Z-isomer 1H NMR (500 MHz, C6D6, 298 K): δ 6.88 (d, J = 5.0 Hz, 0.15H), 6.79 (d, J = 3.5 Hz, 0.14H), 6.75 (m, 0.14H), 6.49 (dq, J = 11.5, 1.8 Hz, 0.15H), 5.48 (qd, J = 11.4, 7.3 Hz, 0.14H), 1.82 (dd, J = 7.2, 1.7 Hz, 0.41H) 412 13C{1H} NMR (126 MHz, C6D6, 298 K): δ 141.2, 126.9, 125.2, 124.6, 123.6, 15.1 1-propen-1-yl-3-bromo-2-thiophenecarboxylate (2q) Synthesis details: substrate 1q, 30 °C, crude E/Z ratio determined by GC = 1:1.9 (E/Z) Reaction time: 24 h Purification details: column chromatography: silica, gradient 0:100 to 8:92 gradient EtOAc/hexanes to give the product as a white, waxy solid (0.242 g, 0.979 mmol, 98% yield). The major product isolated is the Z-isomer, and the E-isomer is seen in the NMR spectra as well. The ratio of these isomers determined by integration of H in the β-position was found to be 1:1.7 (E/Z). Both products are fully characterized below. E-isomer 1H NMR (500 MHz, CDCl3, 298 K): δ 7.51 (d, J = 5.2 Hz, 0.54H), 7.20 (m that overlaps with Z-isomer, 0.56H), 7.12 (d, J = 5.2 Hz, 0.58H), 5.61 (dq, J = 12.3, 7.1 Hz, 0.58H), 1.70 (dd, J = 7.0, 1.7 Hz, 1.82H) 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 158.1, 135.6, 133.36, 132.1, 126.6, 118.2, 111.2, 12.5 Z-isomer 1H NMR (500 MHz, CDCl3, 298 K): δ 7.53 (d, J = 5.2 Hz, 1H), 7.22 (m that overlaps with E-isomer, 1H), 7.14 (d, J = 5.2 Hz, 1H), 5.07 (dq, J = 6.9, 6.3 Hz, 1H), 1.80 (dd, J = 6.9, 1.8 Hz, 3H) 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 158.0, 134.6, 133.43, 132.3, 127.1, 118.0, 109.9, 10.4 IR (ATR, neat) v: 3105-2858 (w), 1726 (s), 1413 (s), 1224 (s), 1075 (s), 880 (m) ASAP/HRMS (m/z): [M+] calculated for C8H7BrO2S 245.9350, found 245.9334 413 2-sulfolene (2r) Synthesis details: substrate 1r, 30 °C. Reaction time: 24 h Reaction workup details: The filtered product was analyzed by NMR to yield a mixture of 2r and 1r (0.118 g, 0.99 mmol, >99% 1r and 2r recovered). The ratio of 1r and 2r was determined by integration of H in the alkene positions for 1r (6.02 ppm, 2H) and for 2r (6.72 ppm, 1H) and the conversion of 1r to 2r was found to 37%. 2r is characterized below by 1H and 13C{1H}. NMR spectra match previously reported values.329 1H NMR (500 MHz, CDCl3, 298 K): δ 6.72 (m, 1H), 6.60 (dt, J = 6.7, 2.2 Hz, 1H), 3.17 (m, 2H), 2.90 (m, 2H) 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 139.3, 131.8, 47.4, 26.5 (1-propen-1-yloxy)benzene (2s) Synthesis details: substrate 1s, 30 °C, crude E/Z ratio determined by GC- MS = 1:2.3 Reaction time: 1 h Purification details: pipette plug: silica, 5:95 Et2O/hexanes to give the product as a colorless oil (0.0976 g, 0.727 mmol, 73% yield). NMR spectra match values previously reported.330–332 The major product isolated is the Z-isomer, and the E-isomer is seen in the NMR spectra as well. The ratio of these isomers determined by integration of H in the β-position was found to be 1:2.8 (E/Z). Because of significant overlap in the aryl region, both isomers are characterized together below. 1H NMR (500 MHz, CDCl3, 298 K): δ 7.35-7.31 (m, 7.1H, E- and Z- isomers), 7.07-6.99 (ms, 10.6H, E- and Z-isomers), 6.45 (m, 1H, E- isomer), 6.41 (m, 2.6H, Z-product), 5.41 (m, 1H, E-isomer), 4.90 (m, 2.6H, Z-isomer), 1.75 (m, 7.7H, Z-isomer), 1.70 (m, 3H, E-isomer) 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 157.7 (Z-isomer), 157.6 (E- isomer), 142.1 (E-isomer), 141.0 (Z-isomer), 129.7 (E- and Z-isomer), 414 122.50 (E-isomer), 122.47 (Z-isomer), 116.4 (E-isomer), 116.3 (Z- isomer), 108.4 (E-isomer), 107.6 (Z-isomer), 12.4 (E-isomer), 9.5 (Z- isomer) N-methyl-N-(prop-1-enyl)-p-toluenesulfonamide (2t) Synthesis details: substrate 1t, 30 °C, crude E/Z ratio determined by GC = 26:1 (E/Z) Reaction time: 24 h Purification details: pipette plug: silica, 0:100 to 20:80 EtOAc/hexane to give the product as a white solid (0.219 g, 0.972 mmol, 97% yield). NMR spectra match values previously reported.333 The major product isolated is the E-isomer, and the Z-isomer is seen in the NMR spectra as well. The ratio of these isomers determined by integration of H in the allyl-methyl position was found to be 24:1 (E/Z). 1H NMR (500 MHz, CDCl3, 298 K): δ 7.62 (d, J = 8.3 Hz, 2H), 7.30 (d, J = 8.0 Hz, 2H), 6.71 (dq, J = 14.0, 1.5 Hz, 1H), 4.71 (dq, J = 13.3, 6.8 Hz, 1H), 2.82 (s, 3H), 2.42 (s, 3H), 1.68 (dd, J = 6.6, 1.5 Hz, 3H) 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 143.7, 134.8, 129.8, 128.4, 127.2, 106.5, 32.4, 21.7, 15.3 N-phenyl-2-butenamide (2u) Synthesis details: substrate 1u, 30 °C, crude E/Z ratio determined by GC = 33:1 Reaction time: 3 h Purification details: column chromatography: silica, gradient 0:100 to 10:90 gradient EtOAc/DCM to give the product as a crystalline white solid (0.147 g, 0.912 mmol, 91% yield). NMR spectra match previously reported values.334 1H NMR (500 MHz, CDCl3, 298 K): δ 7.56 (d, J = 7.0 Hz, 2H), 7.32 (t, J = 8.0 Hz, 2H), 7.15 (br s, 1H), 7.11 (t, J = 7.4 Hz, 1H), 6.99 (dq, J = 15.0, 6.9 Hz, 1H), 5.95 (dq, J = 15.0, 1.7 Hz, 1H), 1.92 (dd, J = 6.9, 1.7 Hz, 3H) 415 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 164.3, 141.6, 138.2, 129.1, 125.6, 124.4, 120.2, 17.9 IR (ATR, neat) v: 3292-2742 (w), 1639 (m), 1443 (m), 1248 (m), 960 (m) 4,4,5,5-tetramethyl-2-1-propen-1-yl-1,3,2-dioxaborolane (2v) Synthesis details: substrate 1v, 30 °C, crude E/Z ratio determined by GC = 8.6:1 (E/Z) Reaction time: 4 h Purification details: Distillation (approximately 0.05 Torr, 25 °C) to give the product as a colorless oil (0.103 g, 0.613 mmol, 61% yield). NMR spectra match values previously reported.228,335,336 The major product isolated is the E-isomer, and the Z-isomer is seen in the NMR spectra as well. The ratio of these isomers determined by integration of H in the allylic methyl position was found to be 8.8:1 (E/Z). The E- product is fully characterized below, and the peaks visible and clearly assignable to the Z-isomer are given directly following the NMR characterization of the E-product. E-isomer: 1H NMR (500 MHz, C6D6, 298 K): δ 6.90 (dq, J = 17.8, 6.4 Hz, 1H), 5.77 (dq, J = 17.8, 1.7 Hz, 1H), 1.63 (dd, J = 6.4, 1.7 Hz, 3H), 1.09 (s, 12H) 13C{1H} NMR (126 MHz, C6D6, 298 K): δ 149.6, 121.7 (br), 82.9, 24.96, 21.6 11B NMR (160 MHz, C6D6, 298 K): δ 30.02 Z-isomer: 1H NMR (500 MHz, C6D6, 298 K): δ 5.72 (m, 0.07H), 2.08 (dd, J = 6.9, 1.6 Hz, 0.35H), 1.07 (s, 1.62H) 13C{1H} NMR (126 MHz, C6D6, 298 K): δ 149.8, 82.7, 24.97 11B NMR (160 MHz, C6D6, 298 K): δ 22.89 IR (ATR, neat) v: 2979-2854 (w), 1642 (m), 1354 (s), 1143 (s), 849 (m) 2-(1-propen-1-yl)phenyl acetate (2w) 416 Synthesis details: substrate 1w, 30 °C, crude E/Z ratio determined by GC- MS = 26:1 (E/Z) Reaction time: 6 h Purification details: pipette plug: silica, 100% pentane to give the product as a colorless oil (0.170 g, 0.965 mmol, 97% yield). NMR spectra values match values previously reported.228 The major product isolated is the E-isomer, and the Z-isomer is seen in the NMR spectra as well. The ratio of these isomers determined by integration of H in the β-position was found to be 16:1 (E/Z). The E-product is fully characterized below, and the peaks visible and clearly assignable to the Z- isomer are given directly following the NMR characterization of the E- product. E-isomer: 1H NMR (500 MHz, CDCl3, 298 K): δ 7.51 (dd, J = 7.6, 1.7 Hz, 1H), 7.24- 7.17 (ms, 2H), 7.01 (dd, J = 7.8, 1.4 Hz, 1H), 6.41 (dq, J = 15.8, 1.8 Hz, 1H), 6.25 (dq, J = 15.8, 6.6 Hz, 1H), 2.34 (s, 3H), 1.90 (dd, J = 6.6, 1.6 Hz, 3H) 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 169.5, 147.6, 130.6, 128.6, 127.8, 126.6, 126.3, 124.41, 122.6, 21.06, 19.0 Z-isomer: 1H NMR (500 MHz, CDCl3, 298 K): δ 7.33 (m, 0.05H), 7.29 (m, 0.03H), 7.07 (dd, J = 7.9, 1.1 Hz, 0.05H), 6.31 (m, 0.05H), 5.87 (dq, J = 11.5, 7.0 Hz, 0.06H), 2.28 (s, 0.11H), 1.78 (dd, J = 7.0, 1.8 Hz, 0.13H) IR (ATR, neat) v: 3053-2848 (w), 1765 (s), 1368 (m), 1201 (s), 962 (w) 1-(4-methylbenzenesulfonate)-2-(2-propen-1-yl)phenol (2x) Synthesis details: substrate 1x, 30 °C, crude E/Z ratio determined by GC- MS = 29:1 Reaction time: 2 h 417 Purification details: column chromatography: silica, 0:100 to 4:96 Et2O/hexanes to give the product as a viscous, colorless oil (0.287 g, 0.997 mmol, >99% yield). The major product isolated is the E-isomer, and the Z-isomer is seen in the NMR spectra as well. The ratio of these isomers determined by integration of H in the β-position was found to be 29:1 (E/Z). 1H NMR (500 MHz, CDCl3, 298 K): δ 7.69 (d, J = 8.3 Hz, 2H), 7.39 (dd, J = 7.4, 2.3 Hz, 1H), 7.28 (d, J = 8.2 Hz, 2H), 7.19-7.13 (ms, 2H), 7.10 (m, 1H), 6.27 (dq, J = 15.9, 1.9 Hz, 1H), 6.00 (dq, J =15.8, 6.6 Hz, 1H), 2.43 (s, 3H), 1.71 (dd, J = 6.6, 1.7 Hz, 3H) 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 146.5, 145.4, 132.9, 131.8, 129.7, 128.7, 128.3, 127.7, 127.2, 126.6, 124.1, 123.2, 21.8, 18.7 IR (ATR, neat) v: 3086-2849 (w), 1597 (m), 1363 (s), 1167 (s), 962 (m) ASAP/HRMS (m/z): [M+] calculated for C16H16O3S 288.0820, found 288.0794 1-bromo-4-(1-propen-1-yl)benzene (2y) Synthesis details: substrate 1y, 30 °C, crude E/Z ratio determined by GC- MS = 42:1 Reaction time: 5 h Purification details: column chromatography, silica, 0:100 to 5:95 Et2O/pentane to give the product as a pale-yellow oil (0.181 g, 0.919 mmol, 92% yield). The major product isolated is the E-isomer, and the Z-isomer is not seen in the NMR spectra. E-isomer 1H NMR (500 MHz, CDCl3, 298 K) δ 7.36 (d, J = 8.4 Hz, 2H), 7.13 (d, J = 8.4 Hz, 2H), 6.29 (d, J = 16.1, 1H), 6.18 (dq, J = 15.7, 6.5 Hz, 1H), 1.84 (dd, J = 6.5, 1.2 Hz, 3H). 418 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 136.9, 131.6, 130.0, 127.5, 126.7, 120.4, 18.6 IR (ATR, neat) v: 3062-2727 (w), 1486 (m), 1070 (m), 966 (s), 840 (s) ASAP/HRMS (m/z): [M+] calculated for C9H9Br 195.9888, found 195.9955 2-decene (2z) Synthesis details: substrate 1z, 30 °C, crude E/Z ratio determined by GC = 3.9:1 Reaction time: 8 h Purification details: pipette plug: silica, 100% pentanes to give the product as a colorless oil (0.124 g, 0.881 mmol, 88% yield). NMR spectra match values previously reported.337–339 The major product isolated is E-2-decene (E-2z), and Z-2-decene (Z-2z) and other decene isomers (3-, 4-, and 5-decene) are seen in the NMR spectra as well (~87% 2-decene isomers and 13% internal isomers in the crude reaction determined by GC). The ratio of the 2-decene isomers determined by integration of H in the terminal methyl group was found to be 8.9:1 (E/Z). E-2z is fully characterized below, and the peaks visible and clearly assignable to Z-2z are given directly following the NMR characterization of the E-product. E-isomer 1H NMR (500 MHz, CDCl3, 298 K): δ 5.43-5.40 (ms, 2H), 1.65 (d, J = 4.1 Hz, 2H), 1.38-1.27 (ms, 12H), 0.89 (t, J = 6.7 Hz, 3H) 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 131.9, 124.7, 32.8, 32.0, 29.8, 29.4, 29.3, 22.8, 18.1, 14.2 Z-isomer 1H NMR (500 MHz, CDCl3, 298 K): δ 1.61 (d, J = 5.9 Hz, 0.56H), 0.97 (t, J = 7.4 Hz, 0.39H) 1-Phenyl-2-butene (2aa) 419 Synthesis details: substrate 1aa, 0 °C, crude E/Z ratio determined by GC = 5.0:1 (E/Z) Reaction time: 2.5 h Purification details: pipette plug: silica, 100% hexanes to give the product as a colorless oil. 0.126 g was isolated with 7.3% 2ab. The amount and yield of 2aa was adjusted to 0.116 g, 0.881 mmol, 88% yield. NMR spectra match values previously reported.230,340 The major product isolated is the E-isomer, and the Z-isomer is seen in the NMR spectra as well. The ratio of these isomers determined by integration of H in the benzylic methylene position was found to be 5.0:1 (E/Z). Also, 7.3% of 2ab is seen. The E-isomer is fully characterized below, and the peaks visible and clearly assignable to the Z-isomer are given directly following the NMR characterization of the E-isomer. E-isomer: 1H NMR (500 MHz, CDCl3, 298 K): δ 7.31 (m, 2H), 7.24-7.18 (ms, 3H), 5.65-5.51 (ms, 2H), 3.35 (d, J = 6.1 Hz, 2H), 1.72 (m, 3H) 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 141.2, 130.2, 128.6, 128.49, 126.5, 126.01, 39.2, 18.0 Z-isomer: 1H NMR (500 MHz, CDCl3, 298 K): δ 3.44 (d, J = 4.0 Hz, 0.41H), 1.76 (d, J =4.1 Hz, 0.57H) 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 141.3, 129.2, 128.55, 126.1, 125.96, 125.0, 33.3, 13.0 1-Phenyl-1-butene (2ab) Synthesis details: substrate 1aa, 70 °C, crude E/Z ratio determined by GC = 36:1 (E/Z) Reaction time: 8 h Purification details: pipette plug: silica, 100% hexanes to give the product as a colorless oil. 0.129 g was isolated with 6.3% 2aa and 3.6% hydrogenated product. The amount and yield of 2ab was adjusted to 0.115 420 g, 0.870 mmol, 87% yield. NMR spectra match values previously reported.341,342 The Z-isomer of 2ab is not observed by NMR. E-2ab and the hydrogenated alkene are also observed, and the ratio of these products are determined by integration of H in the methyl-position was found to be 25:1.6:1 (E-2ab/E-2aa/hydrogenated product). The E-isomer of 2ab is fully characterized below. 1H NMR (500 MHz, CDCl3, 298 K): δ 7.36 (d, m, 2H), 7.30 (t, J = 7.7 Hz, 2H), 7.19 (tt, J = 7.0, 1.3 Hz, 1H), 6.39 (dt, J = 15.9, 1.5 Hz, 1H), 6.28 (dt, 15.9, 6.5 Hz, 1H), 2.26 (quint, J = 7.2 Hz, 2H), 1.11 (t, J = 7.5 Hz, 3H) 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 138.1, 132.8, 129.0, 128.6, 126.9, 126.1, 26.2, 13.8 e. Incompatible Substrates D.1.7. Isomerization Scale-Up Reaction In a nitrogen-filled glovebox, SZO + +300 (2.03 g, 0.425 mmol H , 0.0500 equiv H ), Ni[P(OEt)3]4 (0.185 g, 0.256 mmol, 0.0300 equiv) and Et2O (3.0 mL) were added to a 4-dram vial equipped with a stir bar. The solid immediately turned from white to bright orange. The reaction was capped and gently stirred. After 30 min, the solution was decanted, and the remaining orange solid was washed with Et2O (3 x 3.0 mL). After the third wash, the solid was dried under a flow of nitrogen 421 and transferred into a 250-mL Schlenk flask equipped with a stir bar. Et2O (145 mL) was then added to the flask. The reaction flask was sealed and removed from the glovebox. Allylanisole (1a, 1.31 mL, 8.53 mmol, 1.00 equiv) was added to the flask, placed in a water bath preheated to 30 °C, and the reaction was stirred at 150 rpm. Aliquots (~20 µL) were taken over time to assess reaction progress. The reaction was complete after 2 h, and the selectivity of the reaction prior to workup was determined by GC to be 32:1 (E/Z). The reaction was exposed to air and filtered through Celite. The filtrate was concentrated to obtain 2a as a white solid (1.24 g, 8.37 mmol, 98% yield). The selectivity of 2a was found to be 33:1 (E/Z) by 1H NMR. Figure E.2. 1H NMR spectrum of the scaled-up isomerization of 1a to form 2a taken in CDCl3 at 25 °C. E.1.8. Comparison of Isomerization Rates between 1aa to 2aa and 2aa to 2ab 422 100 80 60 1aa to 2aa 40 2aa to 2ab 20 0 0 20 40 60 80 100 120 Time (min) Figure E.3. Plot of the % yield versus reaction time of the formation of 2aa (pink squares) or 2ab (green circles). 70 1aa to 2aa 60 2aa to 2ab 50 y = 5.591x 40 R² = 0.9942 30 20 y = 0.0992x 10 R² = 0.9964 0 0 2 4 6 8 10 12 Time (min) Figure E.4. Plot of the % yield versus reaction time of the formation of 2aa (pink squares) or 2ab (green circles) and corresponding slopes for the first 10 min. 423 % Yield % Yield 5 4 3 2 1 1aa to 2aa 2aa to 2ab 0 0 20 40 60 80 100 120 Time (min) Figure E.5. Plot of the selectivity versus reaction time of the formation of 2aa (pink squares) or 2ab (green circles). Table E.4. Yield and selectivity (E/Z) of 2aa or 2ab over time for the reaction of 1aa to 2aa (pink squares) and for the reaction of 2aa to 2ab (green circles). 1aa to 2aa Reaction 2aa to 2ab Reaction Time E/Z Selectivity E/Z Selectivity (std (min) % Yield % Yield (std error) error) 2 13.712±0.002 2.67:1 (0.02) 0.21±0.06 0.347:1 (0.004) 4 26±2 2.93:1 (0.08) 0.45±0.04 0.603:1 (0.001) 6 36±2 3.096:1 (0.003) 0.65±0.06 0.90:1 (0.02) 8 45±2 3.2371:1 (0.0003) 0.8±0.1 1.19:1 (0.02) 10 52±4 3.36:1 (0.01) 0.9±0.2 1.57:1 (0.07) 15 64±4 3.64:1 (0.04) 1.5±0.3 2.4:1 (0.2) 20 75.3±0.2 3.90:1 (0.02) 2.0±0.4 3.1:1 (0.2) 30 78±3 4.14:1 (0.05) 2.9±0.6 3.9:1 (0.2) 45 80±2 4.28:1 (0.05) 4.2±0.9 4.26:1 (0.04) 60 79±2 4.33:1 (0.04) 5±1 4.30:1 (0.02) 80 77.0±0.9 4.4:1 (0.2) 6±2 4.315:1 (0.008) 100 74±1 4.39:1 (0.01) 6.3 4.349:1 120 73±2 4.41:1 (0.01) 8±1 4.374:1 (0.008) Comparing the linear portion of the rates of reaction from the first 10 min of 1aa to 2aa and 2aa to 2ab, the rate of reaction of 1aa to 2aa is 55x faster than that of the reaction of 2aa to 2ab. 424 Selectivity (E/Z) E.1.9. Comparison of the Substrate Scope of the Homogeneous and Heterogeneous Catalysts Homogeneous catalyst: In a nitrogen-filled glovebox, a stock solution of Ni[P(OEt)3]4 in Et2O was prepared and distributed into a 1-dram vial equipped with a stir bar using a disposable 1-mL syringe (1.3 mg, 0.0018 mmol, 0.030 equiv was added to each vial). The vial was sealed with a septum cap and brought out of the glovebox. A separate stock solution of H2SO4 (0.16 μL, 0.0030 mmol, 0.050 equiv added to each vial) in Et2O was prepared and then added to the vial using a 25- µL syringe. This addition resulted in an immediate color change to light orange. The total volume of Et2O was 1.0 mL. The alkene (0.060 mmol, 1.0 equiv) was added to the vial using a 25-µL syringe. The reaction was then immediately heated to 30 °C using a preheated aluminum block and stirred at a rate of 150 rpm. The reaction progress was monitored by GC by taking aliquots (~20 µL) over time. The aliquots were diluted with hexanes (1 mL) and filtered through Celite into a GC vial. The reaction time, percent conversion of starting material, and selectivity (E/Z) are shown in Table S4 below and are compared to the analogous results using the heterogeneous catalyst. Heterogeneous catalyst: In a nitrogen-filled glovebox, SZO300 (15 mg, 0.0030 mmol H +, 0.050 equiv H+ per vial) was weighed directly into a 1-dram vial equipped with a stir bar. A stock solution of Ni[P(OEt)3]4 in Et2O was prepared and distributed to the vial using a disposable 1-mL syringe (1.3 mg, 0.0018 mmol, 0.030 equiv was added to each vial). This addition resulted in an immediate color change of the SZO300 from white to bright orange. The total volume of Et2O in the vial was 1.0 mL. The vial was sealed with a septum cap and brought out of the glovebox. The alkene (0.060 mmol, 1.0 equiv) was added to the vial using a 25-µL syringe. The reaction was then immediately heated to 30 °C using a preheated aluminum block and stirred at a rate of 150 rpm. The reaction progress was monitored by GC by taking aliquots (~20 µL) over time. The aliquots were diluted with hexanes (1 mL) and filtered through Celite into a GC vial. The reaction time, percent conversion of starting material, and selectivity (E/Z) are shown in Table S4 below and are compared to the analogous results using the homogeneous catalyst. 425 Table E.5. Comparison of the reaction time, conversion to product, and selectivity of alkene isomerization using Ni[P(OEt)3]4 and H2SO4 or SZO300 with a variety of substrates Reaction Conversion to Product H+ source Selectivity (E/Z) time (h) product H2SO4 24 0% n.d. SZO300 2 99.17±0.03% 8.17±0.09:1 H2SO4 24 1.00±0.05% >99:1 SZO300 7 97.6±0.7% >99:1 H2SO4 0.5 3.0±0.3% e >99:1 SZO300 4 100% a 25:1 H2SO4 7 13.192±0.002% e 1:1.690±0.006 SZO300 7 99.0±0.1% 1:1.9±0.3 H2SO4 1 65.45±0.06% f >99:1 SZO300 7 96.22±0.02% 13.2±0.9:1 H2SO4 0.5 99.20±0.04% 5.4±0.1:1 H2SO4 24 98.9±0.2% b 6.1±0.3:1 SZO a 300 8 98% 19:1 H2SO4 0.5 100±0% c 4.4±0.4:1 H2SO4 24 100±0% d 5.3±0.6:1 SZO300 5 100% a 28:1 H2SO4 TBD TBD TBD SZO300 5 99% a 38:1 e 2.9±0.4:1 H2SO4 1 (0 °C) 90±3% 2aa/2ab = 66±13:1 5.1:1 SZO a 300 2.5 (0 °C) 98% 2aa/2ab = 34:1 2aa E/Z = 5.58±0.08:1 H2SO4 1 (30 °C) 98.8±0.2% 2ab E/Z = 20±1:1 2aa/2ab = 1.47±0.05:1 SZO300 1 (30 °C) 84% a 2aa E/Z = 3.9:1 2ab E/Z = 1:0 426 2aa/2ab = 8:1 >99:1 H2SO4 1 (70 °C) 4.9±0.7% e 2aa/2ab = 1:1.50±0.02 36:1 SZO300 8 (70 °C) 90% a 2aa/2ab = 1:9.3 H2SO4 0.5 100±0% >99:1 SZO300 4 97±2% >99:1 p.r. = positional ratio of major product to other phenyl butene positional isomers n.d. = not determined aOnly one trial was performed and was run on a 1 mmol scale of alkene. b2% of the deprotected product (2-hydroxy-β-methylstyrene 2l) was formed. c1% of the deprotected product (2-hydroxy-β-methylstyrene 2l) was formed. d20% of the deprotected product (2-hydroxy-β-methylstyrene 2l) was formed. eConversion and selectivity remain the same after the reported time point. fConversion remain the same after the reported time point. E.1.10. Comparison of Acid Sources (H2SO4, SZO300, NafionTM, and Amberlyst®-15) a. Comparison of H2SO4 and SZO300 as the Acid Sources General Procedure A. Homogeneous catalyst: In a nitrogen-filled glovebox, a stock solution of Ni[P(OEt)3]4 (2.6 mg, 0.0036 mmol, 0.030 equiv per vial) and cyclooctane (8 μL, 0.06 mmol per vial) was prepared in Et2O and distributed into a 1-dram vial using a disposable 1-mL syringe. The vial was sealed with a septum cap and brought out of the glovebox. A separate stock solution of H2SO4 in Et2O was prepared and the appropriate amount of solution (0.50 M, 12 μL, 0.0060 mmol, 0.050 equiv per vial) was added to the vial using a 25-µL syringe. This addition resulted in an immediate color change to light orange. The total volume of Et2O in the vial was 2.0 mL. The alkene (0.120 mmol, 1.00 equiv) was added to the vial using a 25-µL syringe. The reaction was then immediately heated to 30 °C using a preheated aluminum block and stirred at a rate of 150 rpm. The reaction progress was monitored by GC by taking aliquots (~20 µL) over time. The aliquots were diluted with hexanes (1 mL) and filtered through Celite into a GC vial and analyzing by GC. 427 General Procedure B. Heterogeneous catalyst: In a nitrogen-filled glovebox, SZO300 (30.0 mg, 0.00600 mmol H +, 0.0500 equiv H+ per vial) was weighed into a 1-dram vial equipped with a stir bar. A stock solution of Ni[P(OEt)3]4 (2.60 mg, 0.00360 mmol, 0.0300 equiv per vial) and cyclooctane (8-9 μL per vial) was prepared in Et2O and distributed into a 1-dram vial using a disposable 1-mL syringe. This addition resulted in an immediate color change of the SZO300 from white to bright orange. The total volume of Et2O in the vial was 2.0 mL. The vial was sealed with a septum cap and brought out of the glovebox. The alkene (0.120 mmol, 1.00 equiv) was added to the vial using a 25-µL syringe. The reaction was then immediately heated to 30 °C using a preheated aluminum block and stirred at a rate of 150 rpm. The reaction progress was monitored by GC by taking aliquots (~20 µL) over time. The aliquots were diluted with hexanes (1 mL) and filtered through Celite into a GC vial and analyzed by GC. i. Allylbenzene (1c) Using General Procedure A and B, the yield and E/Z selectivity of the isomerization of 1c (16 uL, 0.12 mmol, 1.0 equiv) was measured over time. The data are seen in Figures S4-S5 and Table S5 below. 428 100 80 60 40 20 homogeneous heterogeneous 0 0 50 100 150 200 Time (min) Figure E.6. Plot of the yields versus reaction time of the formation of 2c using the homogeneous catalyst Ni[P(OEt)3]4/H2SO4 (green circles) and the heterogeneous catalyst Ni[P(OEt)3]4/SZO300 (pink squares). 40 30 20 10 homogeneous heterogeneous 0 0 50 100 150 200 Time (min) Figure E.7. Plot of the selectivity versus reaction time of the formation of 2c using the homogeneous catalyst Ni[P(OEt)3]4/H2SO4 (green circles) and the heterogeneous catalyst Ni[P(OEt)3]4/SZO300 (pink squares). 429 % Yield Selectivity (E/Z) Table E.6. Yield and E/Z selectivity of 2c as a function of time using the homogeneous catalyst Ni[P(OEt)3]4/H2SO4 and the heterogeneous catalyst Ni[P(OEt)3]4/SZO300. Homogeneous catalyst Heterogeneous catalyst Time E/Z Selectivity Time E/Z Selectivity % Yield % Yield (min) (std error) (min) (std error) 5 99±1 18.8:1 (0.2) 3 13±3 11.3:1 (0.6) 10 97±3 28.7:1 (0.2) 7 29±2 13.5:1 (0.1) 20 98±3 35.0:1 (0.2) 12 43±6 15.6:1 (0.5) 30 97±4 35.7:1 (0.3) 18 56.4±0.3 17.74:1 (0.09) 40 97±3 35.8:1 (0.6) 25 66.8±0.3 20.262:1 (0.005) 50 98±3 35.6:1 (0.5) 30 71±6 22.04:1 (0.08) 60 98±3 36.2:1 (0.2) 40 72±5 25.1:1 (0.6) 90 90±4 36.09:1 (0.06) 55 84.7±0.2 30.2:1 (0.3) 120 87±1 36.03:1 (0.3) 90 91±2 35.70:1 (0.08) -- -- -- 120 91.8±0.2 36:1 (1) -- -- -- 180 92±6 37.9:1 (0.6) ii. Allylanisole (1a) Using General Procedure A and B, the yield and E/Z selectivity of the isomerization of 1a (19 uL, 0.12 mmol, 1.0 equiv) was measured over time. The data are seen in Figures S6-S7 and Table S6 below. 430 100 80 60 40 20 heterogeneous homogeneous 0 0 20 40 60 80 100 120 Time (min) Figure E.8. Plot of the yields versus reaction time of the formation of 2a using the homogeneous catalyst Ni[P(OEt)3]4/H2SO4 (green circles) and the heterogeneous catalyst Ni[P(OEt)3]4/SZO300 (pink squares). 40 30 20 10 heterogeneous homogeneous 0 0 20 40 60 80 100 120 Time (min) Figure E.9. Plot of the selectivity versus reaction time of the formation of 2a using the homogeneous catalyst Ni[P(OEt)3]4/H2SO4 (green circles) and the heterogeneous catalyst Ni[P(OEt)3]4/SZO300 (pink squares). 431 % Yield Selectivity (E/Z) Table E.7. Yield and E/Z selectivity of 2a as a function of time using the homogeneous catalyst Ni[P(OEt)3]4/H2SO4 and the heterogeneous catalyst Ni[P(OEt)3]4/SZO300. Homogeneous catalyst Heterogeneous catalyst Time E/Z Selectivity (std Time E/Z Selectivity % Yield % Yield (min) error) (min) (std error) 5 78±3 5.8:1 (0.3) 10 32±3 11.9:1 (0.2) 10 72±4 6.0:1 (0.4) 20 49±4 13.9:1 (0.1) 15 72±1 6.2:1 (0.6) 30 62±3 16.3:1 (0.1) 20 73±4 6.7:1 (0.6) 40 75±6 18.55:1 (0.06) 35 67±4 8.1:1 (0.8) 50 74±3 20.11:1 (0.06) 60 63±3 11:1 (2) 60 80.217±0.006 21.8:1 (0.2) 90 69 14.7:1……. 80 81±2 25.9:1 (0.2) 120 71±3 17:1 (1) 100 88±3 28.6:1 (0.3) -- -- -- 120 90±5 29.8:1 (0.9) -- -- -- 160 94±4 31.9:1 (0.3) -- -- -- 180 88±2 31.7:1 (0.4) Procedure using NafionTM and Amberlyst®-15: In a nitrogen-filled glovebox, a stock solution was prepared by dissolving Ni[P(OEt)3]4 in Et2O. This stock solution was then transferred into a 2- dram scintillation vial, which was then sealed with a septum cap and removed from the glovebox. Outside the glovebox, NafionTM (7.0 mg, 0.0063 mmol H+, 0.048 equiv H+) or Amberlyst®-15 (1.3 mg, 0.0061 mmol H+, 0.047 equiv H+) was added to a 1-dram scintillation vial equipped with stir bar. The vial was sealed with a septum cap and flushed with N2 for 30 min. The stock solution of Ni[P(OEt)3]4 (2.6 mg, 0.0036 mmol, 0.030 equiv) was added to the vial containing the solid acid using a disposable Luer-Lock 3-mL syringe. The total volume of Et2O added to the vial was 2.0 mL. Then, 1a (19 µL, 0.12 mmol, 1.0 equiv) was added, and the reaction was heated to 30 °C on a pre-heated aluminum block and stirred at a rate of 150 rpm. Throughout the course of the reaction, 20-µL aliquots were removed with a 25-µL syringe, diluted with hexanes, and filtered into a GC vial through Celite. The filtrate was analyzed by GC to assess the reaction progress and product selectivity. Two trials were run and the averages and standard deviations of the two trials are reported below. The data are seen in Figures E.10.-E.12. and Table E.8.-E.9. below. The data for SZO300 used in Figures E.10.-E.11 below is the same as was used above in section E.1.10.a.ii. 432 100 80 SZO300 60 Amberlyst 15 Nafion 40 20 0 0 30 60 90 120 150 180 Time (min) Figure E.10. Plot of the yields versus reaction time of the formation of 2a using the heterogeneous catalysts Ni[P(OEt)3]4/SZO300 (pink triangles), Ni[P(OEt)3]4/Amberlyst ®-15 (green squares), and Ni[P(OEt) ] /NafionTM3 4 (blue circles). 35 30 25 20 15 10 SZO300 5 Amberlyst 15 Nafion 0 0 20 40 60 80 100 120 140 160 180 Time (min) Figure E.11. Plot of the selectivity versus reaction time of the formation of 2a using the heterogeneous catalysts Ni[P(OEt)3]4/SZO300 (pink triangles), Ni[P(OEt)3]4/Amberlyst ®-15 (green squares), and Ni[P(OEt)3]4/Nafion TM (blue circles). 433 Selectivity (E/Z) % Yield Table E.8. Yield and E/Z selectivity of 2a as a function of time using the heterogeneous catalysts Ni[P(OEt) ] ®3 4/Amberlyst -15 and Ni[P(OEt)3] TM 4/Nafion . Amberlyst®-15 NafionTM E/Z Selectivity E/Z Selectivity Time (min) % Yield Time (min) % Yield (std error) (std error) 5 3.1±0.5 11.7:1 (0.3) 5 1.0±0.2 1:0… 10 6±1 12:1 (1) 10 2.1±0.2 30:1 (3) 15 7±1 11:1 (1) 15 2.7±0.3 21:1 (4) 20 9±1 12.2:1 (0.3) 20 3.8±0.4 14.2:1 (0.7) 30 13±3 11.3:1 (0.1) 30 6±3 14:1 (2) 40 17±4 11.0:1 (0.4) 45 8±3 14:1 (2) 60 20±3 11.48:1 (0.03) 60 10±4 14.9:1 (0.9) 92 26±3 13:1 (2) 90 13±6 14.0:1 (0.8) 180 40±1 14:1 (2) 132 16±6 16:1 (3) The relative rates of each system were calculated by calculating the slope of the linear portion (the first ~45 min) (Figure S10). 100 SZO300 Amberlyst 15 80 y = 1.7735xNafion R² = 0.9836 60 40 y = 0.4345x y = 0.1851x R² = 0.9935 R² = 0.9993 20 0 0 10 20 30 40 50 Time (min) Figure E.12. Plot of the linear portion of the data from Figure S8. Table E.9. Acid source, rate, and relative rates of the formation of 2a using the heterogeneous catalysts Ni[P(OEt)3]4/Amberlyst ®-15 and Ni[P(OEt) ] /NafionTM3 4 . Acid source (H+) Rate (% yield/min) Rate of SZO300/Rate of H+ SZO300 1.7735 -- Amberlyst®-15 0.4345 4 NafionTM 0.1851 10 b. Isomerization with Ni[P(OEt)3]4/Zr(OH)4•H2SO4 434 % Yield i. Allylanisole (1a) In a nitrogen-filled glovebox, Zr(OH)4•H2SO4 (15.0 mg) was weighed into a 1-dram vial equipped with a stir bar. A stock solution of Ni[P(OEt)3]4 (1.30 mg, 0.00180 mmol, 0.0300 equiv per vial) and cyclooctane (5 μL per vial) was prepared in Et2O and distributed into a 1-dram vial using a disposable 1-mL syringe. The total volume of Et2O in the vial was 1.0 mL. The vial was sealed with a septum cap and brought out of the glovebox. 1a (9.5 µL, 0.030 mmol, 1.0 equiv) was added to the vial using a 25-µL syringe. The reaction was then immediately heated to 30 °C using a preheated aluminum block and stirred at a rate of 150 rpm. The reaction progress was monitored by GC by taking aliquots (~20 µL) over time. The aliquots were diluted with hexanes (1 mL) and filtered through Celite into a GC vial and analyzed by GC. The data for SZO300 used in Table E.10. is the same as was used above in section E.1.10.a.ii. Table E.10. Yield and selectivity (E/Z) of 2a at 80 and 120 min. Ni[P(OEt)3]4/Zr(OH)4•H2SO4 Ni[P(OEt)3]4/SZO300 Time Selectivity (E/Z) (min) % Yield % Yield Selectivity (E/Z) (std error) 80 88±2 20.1±0.6:1 81±2 25.9±0.2:1 120 90±2 27.2±0.1:1 90±5 30±1:1 ii. N-methyl-N-(prop-1-enyl)-p-toluenesulfonamide In a nitrogen-filled glovebox, Ni[P(OEt)3]4 (21.7 mg, 0.0300 mmol, 0.0300 equiv), Zr(OH)4•H2SO4 (250 mg), and Et2O (17 mL) were added to a 4-dram scintillation vial equipped with a stir bar. The vial was sealed with a septum cap, brought out of the glovebox, injected with 1t (0.221 mL, 1.00 mmol, 1.00 equiv) using a 250-µL syringe, and heated at 30 °C on a preheated aluminum vial block for 24 h. The reaction was stirred at a rate of 150 rpm. After 24 h, the reaction was removed from heat, opened to air, and the solution was filtered through Celite, washing Et2O (2.0 mL). The filtrate was concentrated and analyzed by 1H NMR. 435 Figure E.12. 1H NMR spectrum of the crude reaction for the isomerization of 1t by Ni[P(OEt)3]4/Zr(OH)4•H2SO4 recorded in CDCl3 at 25 °C. Table E.11. Corresponding compound in crude reaction, 1H NMR integration, # of protons, normalized protons, and relative amounts of each compound in the 1H NMR. Chemical shift Relative Compound Integration #H Normalized H (ppm) amount (%) S1 4.36 0.57 1 0.56 32 1t 3.63 0.34 2 0.17 9 E-2t 6.70 1.00 1 1.0 56 Z-2t 1.75 0.17 3 0.057 3 436 E.1.11. Grafted Catalyst ([Ni]-SZO) in Catalysis a. Preparation of Grafted Catalyst In a nitrogen-filled glovebox, SZO300 (150 mg, 0.0300 mmol H +, 1.60 equiv H+), Ni[P(OEt)3]4 (13.5 mg, 0.0187 mmol, 1.00 equiv), and Et2O (1.0 mL) were added into a 4-dram vial equipped with a stir bar. The white SZO300 solid immediately turns into a bright orange color. The vial was sealed with a Teflon-lined thermoset cap and was gently stirred at room temperature for 1.5 h. The liquid was decanted from the orange solid, and the solid was washed three times with Et2O (3 x 1.0 mL). The Et2O reaction solution and washes were combined, and an aliquot of the washings (0.30 mL) was added to an NMR tube with C6D6 (0.3 mL) and analyzed by 31P NMR using tetraethyl-ethylenediphosphonate (3.0 µL, 0.0113 mmol) as an internal standard to quantify the amount of Ni[P(OEt)3]4 remaining in solution. The solid was dried under vacuum (10 -5 mbar) overnight to yield Ni[P(OEt)3]4/SZO300 as a free-flowing orange powder. The IR spectrum and 1H MAS NMR were recorded (Figures E.13.-E.16. and Table E.12.). Digestion of Ni[P(OEt)3]4/SZO300 in 70% aqueous trace metal HNO3 at 25 °C for one week, and quantification of Ni by ICP-MS gives 8.41x10-8 mmol Ni•g-1. 1H MAS (500 MHz, 298 K): δ 4.09 (CH2), 1.28 (CH3), -12.10 (Ni–H), -14.21 (Ni–H) 13C MAS (126 MHz, 298 K): δ 61.8, 15.5 31P MAS (202 Hz, 298 K): δ 134.28 IR (FT, neat pellet) v: 1933 (Ni–H) 437 Figure E.13. 1H solid-state NMR of the grafted catalyst [Ni]-SZO300 recorded under spinning rate of 35 kHz. Acquisition with 96 scans and a recycle delay of 3 s recorded at 25 °C. Asterisks denote spinning side bands. Figure E.14. 13C solid-state NMR of the grafted catalyst [Ni]-SZO300 recorded under spinning rate of 25 kHz. Acquisition with 39089 scans recorded at 25 °C. 438 SZO300 Ni[P(OEt)3]4 Ni/SZO300 Grafted Material 3550 3050 2550 2050 1550 1050 550 Wavenumber (cm-1) Figure E.15. IR of SZO300 (top, pink), Ni[P(OEt)3]4 (middle, teal), and [Ni]-SZO300 (bottom, orange). Figure E.16. 31P{1H} NMR spectrum of the Et2O washings from the grafting study recorded in C6D6 at 25 °C. 439 Table E.12. Integration of labelled peaks in the 31P{1H} NMR spectrum, normalized integrations (integration/#H) of each species in solution, and calculated concentration of Ni[P(OEt)3]4. Amount of Chemical Normalized Compound Integration # of P Ni[P(OEt)3]4 shift (ppm) integration (mM) Internal 29.20 10.00 2 5.00 N/A standard Ni[P(OEt)3]4 158.95 0.67 4 0.168 0.635 The amount of Ni[P(OEt)3]4 grafted onto SZO300 is calculated to be 9.82 mg Ni[P(OEt)3]4. Therefore, a total of 73% Ni[P(OEt)3]4 was grafted onto SZO300, and Ni[P(OEt)3]4 constitutes 6.15 wt. % of the overall grafted catalyst using a 3:5 Ni[P(OEt)3]4/SZO300 ratio. This wt. % Ni value is used to determine the amount of grafted catalyst added to each reaction. b. Isomerization of 1c by the Grafted Catalyst ([Ni]-SZO) Procedure using in situ catalyst: General Procedure B was followed, and the % conversion to 2c and selectivity (E/Z) of the isomerization of 1c (16 µL, 0.12 mmol, 1.0 equiv) was monitored by GC over time. % Conversion of 1c to 2c and selectivity (E/Z) is reported, and the data is seen in Figure E.17. and Table E.13. below. Procedure using grafted catalyst: In a nitrogen-filled glovebox, [Ni]-SZO grafted catalyst (30.0 mg, 0.00255 mmol Ni, 0.0213 equiv) was weighed into a 1-dram vial equipped with a stir bar. To this was added Et2O (2.0 mL) using a disposable 3-mL syringe and sealed with a septum cap. The reaction was immediately injected with 1c (16 µL, 0.12 mmol, 1.0 equiv) using a 25-µL syringe and gently stirred. The reaction progress was monitored by GC by taking aliquots (~20 µL) over time. The aliquots were diluted with hexanes (1 mL) and filtered through Celite into a GC vial and analyzed by GC. % Conversion of 1c to 2c and selectivity (E/Z) is reported, and the data is seen in Figure E.17. and Table E.13. below. 440 100 80 60 40 20 grafted catalyst in situ catalyst 0 0 20 40 60 80 100 Time (min) Figure E.17. Plot of the % conversion to 2c versus reaction time using the in situ generated catalyst Ni[P(OEt)3]4/SZO300 (pink squares) and the grafted catalyst [Ni]-SZO300 (blue circles). 40 30 20 10 grafted catalyst in situ catalyst 0 0 20 40 60 80 100 Time (min) Figure E.18. Plot of the selectivity (E/Z) of 2c versus reaction time using the in situ generated catalyst Ni[P(OEt)3]4/SZO300 (pink squares) and the grafted catalyst [Ni]-SZO (blue circles). 441 Selectivity (E/Z) % Conversion to 2c Table E.13. % Conversion to 2c and E/Z selectivity of 2c as a function of time using the in situ generated and the grafted Ni[P(OEt)3]4/SZO300 catalysts. in situ catalyst Grafted catalyst Time E/Z Selectivity E/Z Selectivity % 2c % 2c (min) (std error) (std error) 5 31±5 12.2:1 (0.9) 40.69±3 13.6:1 (0.8) 10 53±3 14.1:1 (0.3) 63 16:1 15 73±1 16.50:1 (0.07) 79.3±0.5 18.1:1 (0.2) 20 82.2±0.8 19:1 (1) 84.72±0.05 20.06:1 (0.09) 25 88.8±0.3 21.4:1 (0.5) 89±1 21.8:1 (0.4) 30 91±1 23.4:1 (0.8) 93±1 24.9:1 (0.4) 47 96±2 29:1 (2) 96.6±0.2 29.9:1 (0.7) 61 99.3±0.4 34.0:1 (0.9) 99.44±0.05 35.0:1 (0.8) 90 99.7±0.4 35.1:1 (0.7) 99.8±0.3 37.33:1 (0.01) c. [Ni]-SZO Air Stability Test The [Ni]-SZO grafted catalyst (60.1 mg) was weighed directly into an 8 mL vial, sealed with a Teflon-lined thermoset cap, and removed from the glovebox. The vial of catalyst was placed in the fumehood, the Teflon-lined thermoset cap was removed, and the progression of catalyst exposure to ambient atmosphere was documented through photographs over time (Figure E.19.). Figure E.19. Visual representation of exposing the grafted Ni/SZO300 material to atmosphere over time. 442 After exposing the vial of [Ni]-SZO grafted catalyst to ambient atmospheric conditions for 1 h, a stir bar was added, the vial was sealed with a septum cap, and the vial was flushed with nitrogen for 10 min. To this was added Et2O (3.7 mL) using a disposable 3-mL syringe and 1c (30 µL, 0.23 mmol, 1.0 equiv) using a 50 µL-syringe. The reaction was immediately heated to 30 °C using a preheated aluminum vial block and stirred at a rate of 150 rpm. Reaction progress was monitored by GC by taking aliquots (~20 µL) over time. The aliquots were diluted with hexanes (1 mL) and filtered through Celite into a GC vial and analyzed by GC. No isomerization activity was observed after 1.5 h, indicating that the catalyst fully decomposes after exposure to air for 1 h. E.1.12. Catalyst Stability and Heterogeneity Experiments a. Catalyst Aging Tests The General Procedures A and B was followed with the following exceptions: • For the homogeneous catalyst using H2SO4: o The cyclooctane was excluded from the stock solution of Ni[P(OEt)3]4 o The vial was set aside to age for 24 h after addition of the H2SO4 stock solution o Cyclooctane (8.0 µL, 0.059 mmol) was added to the vial just before the addition of 1c • For the heterogeneous catalyst using SZO300: o The cyclooctane was excluded from the stock solution of Ni[P(OEt)3]4 o The vial was sealed with a Teflon-lined cap and set aside in the glovebox to age for 24 h after addition of the Ni[P(OEt)3]4 stock solution to the SZO300 o Cyclooctane (8.0 µL, 0.59 mmol) was added to the vial just before the addition of 1c The data are seen in Figures E.20.-E.21. and Table E.14.-E.15. below. The data in Figures E.20.-E.21. for the fresh homogeneous and heterogeneous catalysts are duplicated from section E.1.10.a.i. 443 100 80 60 40 fresh Ni[P(OEt)3]4/SZO300 24 h Ni[P(OEt)3]4/SZO300 20 fresh Ni[P(OEt)3]4/H2SO4 24 h Ni[P(OEt)3]4/H2SO4 0 0 30 60 90 120 150 180 Time (min) Figure E.20. Plot of yield versus time of the formation of 2c using freshly prepared Ni[P(OEt)3]4/SZO300 (pink filled squares), aged Ni[P(OEt)3]4/SZO300 (pink hollow squares), freshly prepared Ni[P(OEt)3]4/H2SO4 (green filled circles), and aged Ni[P(OEt)3]4/H2SO4 (green hollow circles). 40 30 20 10 fresh Ni[P(OEt)3]4/SZO300 24 h Ni[P(OEt)3]4/SZO300 fresh Ni[P(OEt)3]4/H2SO4 0 0 30 60 90 120 150 180 Time (min) Figure E.21. Plot of selectivity versus time of the formation of 2c using freshly prepared Ni[P(OEt)3]4/SZO300 (pink filled squares), aged Ni[P(OEt)3]4/SZO300 (pink hollow squares), and freshly prepared Ni[P(OEt)3]4/H2SO4 (green filled circles). Error bars are present but are not visible. 444 % Yield Selectivity (E/Z) Table E.14. Yield and E/Z selectivity of 2c over time using freshly prepared and aged Ni[P(OEt)3]4/ SZO300. Fresh catalyst Aged catalyst Time E/Z Selectivity E/Z Selectivity (std (min) % Yield % Yield (std error) error) 3 13±3 11.3:1 (0.6) 15±2 13.98:1 (0.02) 7 29±2 13.5:1 (0.1) 29±1 14.61:1 (0.02) 12 43±6 15.6:1 (0.5) 43±1 15.8:1 (0.2) 18 56.4±0.3 17.74:1 (0.09) 59±1 17.5:1 (0.5) 25 66.8±0.3 20.262:1 (0.005) 71±5 19.5:1 (0.5) 30 71±6 22.04:1 (0.08) 78±4 21.3:1 (0.6) 40 72±5 25.1:1 (0.6) 81±3 24.1:1 (0.4) 55 84.7±0.2 30.2:1 (0.3) 91±8 27.8:1 (0.2) 90 91±2 35.70:1 (0.08) 99±1 34.6:1 (0.3) 120 91.8±0.2 36:1 (1) 98.3±0.5 36.4:1 (0.5) 180 92±6 37.9:1 (0.6) 95±5 36.3:1 (0.3) Table E.15. Yield and E/Z selectivity of 2c over time using freshly prepared and aged Ni[P(OEt)3]4/H2SO4. Fresh catalyst Aged catalyst Time E/Z Selectivity E/Z Selectivity (std (min) % Yield % Yield (std error) error) 5 99±1 18.7:1 (0.2) 0 -- 10 97±3 28.7:1 (0.2) 0 -- 20 98±3 35.0:1 (0.2) 0 -- 30 97±4 35.7:1 (0.3) 0 -- 40 97±3 35.8:1 (0.6) 0 -- 50 98±3 35.6:1 (0.5) 0 -- 60 98±3 36.2:1 (0.2) 0 -- 90 90±4 36.09:1 (0.06) 0 -- 120 87±1 36.0:1 (0.3) 0 -- b. Hot-Filtration Test In a nitrogen-filled glovebox, [Ni]-SZO (31.5 mg, 0.00268 mmol Ni, 0.0222 equiv) was weighed into a 1-dram vial equipped with a stir bar. To this was added cyclooctane (10 μL per vial) using a 25-µL syringe and Et2O (2.0 mL) using a disposable 3-mL syringe. The vial was sealed with a septum cap and 1a (18.0 µL, 0.120 mmol, 1.00 equiv) was added to the vial using a 25-µL syringe. 445 After 20 min of reaction time, the reaction was filtered through a 0.1 µm PTFE syringe filter directly into a 1-dram vial equipped with a stir bar. This process separated the solid catalyst from the solution. The reaction progress of the filtrate was monitored by GC by taking aliquots (~20 µL) over time. The GC aliquots were diluted with hexanes (1 mL) and filtered through Celite into a GC vial and analyzed by GC. Another set of reactions was prepared in the same fashion except was not filtered throughout the reaction. All reactions were run in duplicate. Quantification of Ni by ICP-MS of the reaction filtrates gives 0.00014±0.00001 mmol Ni leached into solution, therefore 5.1±0.5% of [Ni] on the heterogeneous catalyst leached into solution. The data in Figures E.22.-E.23. for non-filtered reaction were obtained as described in General Procedure B. The data are seen in Figures E.22.-E.23. and Table E.16. below. 100 80 60 40 20 Standard Conditions Filtered Reaction 0 0 20 40 60 80 100 120 Time (min) Figure E.22. Plot of yield versus time of the formation of 2a of the non-filtered reaction (pink squares) and filtered reaction (green circles). 446 % Yield 35 Standard Conditions 30 Filtered Reaction 25 20 15 10 5 0 0 20 40 60 80 100 120 Time (min) Figure E.23. Plot of the selectivity versus reaction time of the formation of 2a of the non-filtered reaction (pink squares) and filtered reaction (green circles). Table E.16. Yield and selectivity (E/Z) of 2a over time for the non-filtered reaction (pink squares) and the filtered reaction (green circles). Non-Filtered Reaction Filtered Reaction Time E/Z Selectivity E/Z Selectivity (std (min) % Yield % Yield (std error) error) 3 14.6±0.8 9.027:1 (0.002) 14.82±0.04 9.0:1 (0.2) 6 24±1 9.5:1 (0.2) 24±2 10.3:1 (0.7) 10 33±3 10.5:1 (0.1) 34±3 10.6:1 (0.4) 15 43.9±0.5 11.4:1 (0.2) 44±2 12.010:1 (0.002) 19 52.7±0.1 12.3:1 (0.1) 51±2 12.7:1 (0.1) 25 65±1 13.8:1 (0.2) 53±2 12.9:1 (0.2) 30 66±4 15.1:1 (0.5) 53.3±0.8 13.0:1 (0.3) 40 78±6 17.5:1 (0.8) 54±1 13.072:1 (0.002) 50 79±5 20:1 (1) 53±1 13.13:1 (0.05) 60 80.6±0.2 23.2:1 (0.3) 54±1 13.3:1 (0.3) 75 87±6 25:1 (2) 53±1 13.3:1 (0.4) 90 91±6 28:1 (3) 53±1 13.5:1 (0.6) 105 95±2 30:1 (2) 53±1 13.2:1 (0.1) 120 95.33±0.07 32:1 (3) 53±1 13.2:1 (0.2) As timed aliquots were filtered through Celite, a control experiment was performed to rule out the possibility of Celite quenching the homogeneous [Ni] catalyst that leaches into solution was performed. This was tested by monitoring 1a isomerization by GC in the presence of Celite. 447 Selectivity (E/Z) The General Procedure B was followed with the addition of Celite 545 powder (0.0150 g, 0.142 mmol, 2.40 equiv) to the reaction mixture after combining Ni[(POEt3)4 and SZO300. 100 80 60 40 20 Standard Conditions Celite Reaction 0 0 20 40 60 80 100 120 Time (min) Figure E.24. Plot of yield versus time of the formation of 2a for the reaction at standard conditions (pink squares) and the reaction in the presence of Celite (green circles). 30 Standard Conditions 25 Celite Reaction 20 15 10 5 0 0 20 40 60 80 100 120 Time (min) Figure E.25. Plot of the selectivity versus reaction time of the formation of 2a for the reaction at standard conditions (pink squares) and the reaction in the presence of Celite (green circles). 448 % Yield Selectivity (E/Z) Table E.17. Yield and selectivity (E/Z) of 2a over time for the reaction run at standard conditions (pink squares) and for the reaction in the presence of Celite (green circles). Standard Conditions Celite Reaction Time E/Z Selectivity E/Z Selectivity (min) % Yield % Yield (std error) (std error) 10 32±3 11.9:1 (0.2) 28 11.4:1 (0.7) 20 49±4 13.9:1 (0.1) 42 12.64:1 (0.02) 30 62±3 16.3:1 (0.1) 55.84 14.24:1 (0.04) 40 75±6 18.55:1 (0.06) 62 15.9:1 (0.1) 50 74±3 20.11:1 (0.06) 73 17.73:1 (0.06) 60 80.217±0.007 21.8:1 (0.2) 77 19.1:1 (0.6) 80 81±2 25.9:1 (0.2) 78 22:1 (1) 100 88±3 28.6:1 (0.3) 86 25:1 (2) 120 90±5 29.8:1 (0.9) 89 27:1 (2) 160 94±4 31.9:1 (0.3) -- -- 180 88±2 31.7:1 (0.4) -- -- c. Recyclability Study In a nitrogen-filled glovebox, SZO + +300 (15 mg, 0.0030 mmol H , 0.050 equiv H ) was added to a 1- dram vial equipped with a stir bar. Ni[P(OEt)3]4 (1.3 mg, 0.0018 mmol, 0.030 equiv added to the vial), cyclooctane (5 µL, 0.04 mmol added to the vial), and 1c (8.0 µL, 0.060 mmol, 1.0 equiv added to the vial) were added to the vial using a disposable 1-mL syringe as a stock solution in Et2O. The total volume of Et2O added to each vial was 1.0 mL. The solid immediately turned bright orange upon addition of the stock solution. The vial was sealed with a septum cap and stirred for 1 h 10 min. Stirring was ceased, and the solids were allowed to settle to the bottom. The reaction vial was opened, and the solution was decanted and filtered through Celite. An aliquot (~20 µL) of the filtrate was removed from this solution, placed in a GC vial, diluted with hexanes (1 mL), and analyzed by GC. A separate stock solution of cyclooctane and allylbenzene was prepared in Et2O using volumetric glassware, transferred into a 5-dram scintillation vial, and sealed with a Teflon-lined thermoset cap when not in use. *** The solid, which remained in the reaction vial, was dried by flowing nitrogen over it for 5 min. A portion of the cyclooctane/allylbenzene (8.0 µL, 0.060 mmol, 1.0 equiv allylbenzene and 5 μL, 0.04 mmol cyclooctane added to each vial) 449 stock solution was added to the dried solid using a 1-mL syringe. The reaction was sealed and stirred for the allotted amount of time detailed below in Table SX. The reaction vial was opened, and the solution was decanted and filtered through Celite. An aliquot (~20 µL) of the filtrate was removed from this solution, placed in a GC vial, diluted with hexanes (1 mL), and analyzed by GC. This process starting from *** above was repeated 3 times using the cyclooctane and allylbenzene stock solution for a total of 5 cycles. After the 5th cycle, the reaction solution was decanted, the catalyst was dried using a flow of N2, and the reaction vial was capped and placed in the freezer to store overnight along with the stock solution. The next day, the reaction vial and stock solution were removed, allowed to warm room temperature, and the recyclability studies were continued, starting the process again at *** for a total of 10 cycles. The data are seen in Figures E.26. and Table E.18. below. 40 100 75 30 50 20 25 10 0 0 1 2 3 4 5 6 7 8 9 10 Yield E/Z Cycle Figure E.26. Bar graph of the yield (left axis, solid pink bars) and E/Z selectivity (right axis, striped blue bars) of 2c versus cycle number. Table E.18. The yield and E/Z selectivity of the isomerization of 1c per cycle. E/Z Selectivity (std Cycle Reaction time (h) % Yield error) 1 1.17 97.7±0.1 35.4:1 (0.1) 2 1 99±5 34:1 (4) 3 1 86±10 27:1 (4) 4 1 85±13 26:1 (3) 5 2.5 97.7±0.8 37.7:1 (0.8) Decanted solution, dried catalyst, sealed vial, and placed in freezer overnight. 6 1 84±1 23:1 (1) 7 1.17 92±2 29:1 (2) 8 2 92±1 29.5:1 (0.3) 450 % Yield Selectivity (E/Z) 9 1 88±12 25:1 (3) 10 1 96±4 32:1 (5) No significant catalyst decomposition was observed after 10 cycles. E.1.13. Mechanistic Investigation a. Reactivity with Vinylcyclopropane Using General Procedure B, 1ac (9.0 µL, 0.060 mmol, 1.0 equiv) was employed as the alkene, and the reaction was performed at 30, 50, and 70 °C, separately. The crude reaction was analyzed by GC. Two trials were performed for both experiments. Table S13 displays the data for the trails run for 24 h at 30, 50, and 70 °C. No conversion of 1ac was observed.239 The data are seen in Table E.19. below. Table E.19. Temperature, solvent, % 1ac remaining, and % conversion to 2ac. % conversion to other Temperature (°C) solvent % 1ac remaining rearrangement products 30 Et2O 100 0 50 Et2O 100 0 70a hexanes 100 0 a6 h b. Reactivity with a 1,6-diene Using General Procedure 6a, 1ad was employed as the alkene. After 5 h of stirring at 30 °C, the reaction was opened to air, filtered through Celite, washed with hexanes (1 mL), and concentrated to obtain a crude oil. The crude product was purified via a pipette plug (silica; 100% pentane). 1H NMR spectrum matches previously reported values.216 The data are seen in Figure S16 below. 451 Figure E.27. 1H NMR spectrum for the crude reaction mixture from Ni[P(OEt)3]4/SZO300- catalyzed isomerization of 1ad in CDCl3 at 25 °C. The major product of the reaction was found to be E,E-2ad (77%), E,Z-2ad (20%), and E-1ad (3%) as determined by GC analysis. No formation of the radical cyclization product was observed. c. Deuterium Crossover Experiment In a nitrogen-filled glovebox, SZO300 (141 mg, 0.0281 mmol H +, 0.0500 equiv H+), Ni[P(OEt)3]4 (12.2 mg, 0.0169 mmol, 0.0300 equiv), and Et2O (9.60 mL) were added to a 1-dram scintillation vial equipped with a stir bar. The vial was sealed with a septum cap and brought out of the glovebox. 1a (44 µL, 0.28 mmol, 0.50 equiv) and 1c-dn (40 µL, 0.28 mmol, 0.50 equiv) were added to the vial using a 50-µL syringe. The reaction was then immediately heated to 30 °C using a preheated aluminum block and stirred at a rate of 150 rpm. After 2.5 h (reaction completion 452 determined by GC-MS), the reaction was opened to air and the solution was filtered through Celite, washing Et2O (1.0 mL). The filtrate was concentrated, and the product was purified by column chromatography (silica, 0:100 to 8:92 Et2O/hexanes) to separate 2a-dn from 2c-dn. The products of the reaction were analyzed by 1H (in CDCl3) and 2H NMR (in CHCl3/CDCl3, 5:1). 2H NMR shows deuterium incorporation into all positions along the allyl group in both products 2a-dn and 2c-dn. The density of 1c-dn was determined by measuring 10 μL of sample using a 25-μL syringe and measuring the weight of the sample; this was repeated three times, and the average of the three trials was found to be 0.85 ± 0.06 g/mL. The data are seen in Figures E.28.-E.31. below. Figure E.28. 2H NMR spectrum of 2c-dn after isomerization of 1c-dn in the presence of 1a recorded in CHCl3/CDCl3 (5:1) at 25 °C. 453 Figure E.29. 1H NMR spectrum of 2c-dn after isomerization of 1c-dn in the presence of 1a recorded in CDCl3 at 25 °C. Figure E.30. 2H NMR spectrum of 2a-dn after isomerization of 1a in the presence of 1c-dn recorded in CHCl3/CDCl3 (5:1) at 25 °C. 454 Figure E.31. 1H NMR spectrum of 2a-dn after isomerization of 1a in the presence of 1c-dn recorded in CDCl3 at 25 °C. E.1.14. Comparison to Other Homogeneous Isomerization Catalysts a. (IPr)2Ni2Cl2 Reaction conditions and procedure were taken from literature.228 In a nitrogen-filled glovebox, (IPr)2NiCl2 (see Table S14 for amounts) was directly weighed into a 2-dram vial equipped with a stir bar. To this vial was then added cyclooctane (internal standard; 8 or 12 µL, 0.059 or 0.089 mmol) using a 25-µL syringe and ClC6H5 (0.3 or 0.6 mL, 0.4 M) using a disposable 6-mL syringe. The vial was sealed with a septum cap, removed from the glovebox, injected with 1a (1.0 equiv, either nitrogen-sparged or not see Table S14 for amounts) using a 25-µL syringe, and placed on a 455 pre-heated aluminum vial block set to 30 °C. The reaction was stirred at a rate of 150 rpm. Reaction progress was monitored by GC analysis by taking aliquots (~5 µL) of the solution over time; the aliquots were diluted with 1 mL hexanes and filtered through Celite into a GC vial. Two trials were run, and the averages and standard deviations are reported below. Table S14 below shows the corresponding amount of (IPr)2NiCl2 and 1a used for each experiment. The data are seen in Table S15 and Figures S21-S22 below. Table E.20. The amounts and equivalents of (IPr)2Ni2Cl2 and ClC6H5 and indication if the alkene was nitrogen-sparged for the experiments. (IPr)2NiCl2 1a Cl-C6H5 Nitrogen- Volume mol % mg mmol equiv µL mmol equiv sparged (mL) 1.5 1.6 0.0018 0.015 19 0.12 1.0 no 0.3 1.5 3.3 0.0036 0.015 39 0.25 1.0 yes 0.6 5 5.7 0.0060 0.050 19 0.12 1.0 yes 0.3 100 5 mol % (IPr)2Ni2Cl2 NS 1.5 mol % (IPr)2Ni2Cl2 NS 80 1.5 mol % (IPr)2Ni2Cl2 60 40 20 0 0 30 60 90 120 150 180 Time (min) Figure E.32. Plot of the yield of 2a versus time using 5 mol % (IPr)2Ni2Cl2 with degassed alkene (light pink filled rectangles), 1.5 mol % (IPr)2Ni2Cl2 with degassed alkene (dark pink hollow rectangles), and 1.5 mol % (IPr)2Ni2Cl2 without degassing alkene prior to isomerization (red crosses) at 30 °C. NS, nitrogen-sparged. 456 % Yield 40 20 5 mol % (IPr)2Ni2Cl2 NS 0 0 30 60 90 120 150 180 Time (min) Figure E.33. Plot of the selectivity of 2a versus time using 5 mol % (IPr)2Ni2Cl2 with degassed alkene (light pink filled rectangles), 1.5 mol % (IPr)2Ni2Cl2 with degassed alkene (dark pink hollow rectangles), and 1.5 mol % (IPr)2Ni2Cl2 without degassing alkene prior to isomerization (red crosses) at 30 °C. NS, nitrogen-sparged. Table E.21. Yield and E/Z selectivity of 2a over time catalyzed by 1.5 mol % and 5 mol % (IPr)2Ni2Cl2 with and without degassed alkene at 30 °C. NS, nitrogen-sparged. 1.5 mol % (IPr)2Ni2Cl2 1.5 mol % (IPr)2Ni2Cl2 5 mol % (IPr)2Ni2Cl2 Time Not NS alkene NS alkene NS alkene (min) E/Z Selectivity (std E/Z Selectivity E/Z Selectivity % Yield % Yield % Yield error) (std error) (std error) 3 0.241±0.002 1:0 -- -- -- -- 5 -- -- 0.7±0.1 1:0 4.0±0.2 13:1 (2) 6 0.56±0.07 1:0 -- -- -- -- 9 0.89±0.08 1:0 -- -- -- -- 10 -- -- 1.6±0.1 1:0 9.2±0.7 17.3:1 (0.4) 15 1.6±0.1 1:0 -- -- -- -- 20 2.0±0.1 23:1 (1) 3.654±0.001 20.7:1 (0.7) 21±2 19:1 (2) 30 3.1±0.3 24:1 (3) 5.5±0.3 22:1 (2) 32.2±0.7 21.1:1 (0.7) 45 4.2±0.3 22:1 (1) 7.4±0.6 22:1 (1) 48±2 23.9:1 (0.4) 60 4.6±0.3 23:1 (2) 10±1 22:1 (2) 59±2 32:1 (7) 80 -- -- 13±2 26:1 (3) 72±1 30.43:1 (0.04) 93 5.6±0.6 21.211:1 (0.0006) -- -- -- -- 100 6±1 -- 14.5±0.5 22:1 (4) 80±2 28:1 (2) 120 5.7±0.9 22:1 (1) 16±1 23:1 (2) 84±5 32:1 (6) 150 5±1 22.0:1 (0.7) 20±1 25:1 (3) 87±4 30.43:1 (0.04) 180 5±1 23.6:1 (0.3) 21±1 22:1 (1) 92±1 37:1 (6) 457 Selectivity (E/Z) b. Ni(cod)2 + PCy3•HBF4 + NBu4Br Reaction conditions and procedure were taken from literature with slight modifications.229 In a nitrogen-filled glovebox, Ni(cod)2 (see Table S16 below for amounts), PCy3•HBF4 (see Table S16 below for amounts), and tetrabutylammonium bromide (40 mg, 0.12 mmol, 0.50 equiv) were directly weighed into a 1-dram scintillation vial equipped with a stir bar. To this vial was added DMF (5.0 mL) using a disposable 6 mL-syringe and cyclooctane (internal standard; 8.0-10 μL,0.059-0.074 mmol added to the vial) using a 25-µL syringe. The vial was sealed with a septum cap, brought out of the glovebox, injected with nitrogen-sparged H2O (2.5 µL, 0.14 mmol, 0.56 equiv) using a 10-µL syringe followed by 1a (39 µL, 0.25 mmol, 1.0 equiv) using a 50-µL syringe, and heated at 30 °C on a preheated aluminum vial block. The reaction was stirred at a rate of 150 rpm. Throughout the course of the reaction, 40-µL aliquots were removed with a 50-µL syringe, diluted with hexanes, and filtered into a GC vial through Celite. The filtrate was analyzed by GC to assess the reaction progress and product selectivity. Two trials were run for all experiments and the averages and standard deviations for the two trials are reported below in Table E.23. and the data is seen in Figure E.34.-E.35. Table E.22. The catalyst loading, amount, and mmol of Ni(cod)2 and PCy3•HBF4 for each experiment. Reaction Ni(cod)2 PCy3•HBF4 conditions mol % mg mmol mol % mg mmol Standard (30 10 7.0 0.025 11 10 0.027 °C) Ours 3 2.1 0.0076 3 2.8 0.0076 (30 °C) 458 100 10:11 mol % Ni(cod)2/PCy3HBF4 3:3 mol % Ni(cod)2/PCy3HBF4 80 60 40 20 0 0 30 60 90 120 150 180 210 Time (min) Figure E.35. Plot of the yield of 2a versus reaction time using 10 mol % Ni(cod)2 and 11 mol % PCy3•HBF4 (blue filled circles) and 3 mol % Ni(cod)2 and mol % PCy3•HBF4 (blue hollow circles) at 30 °C. 20 15 10 5 10:11 mol % Ni(cod)2/PCy3HBF4 3:3 mol % Ni(cod)2/PCy3HBF4 0 0 30 60 90 120 150 180 210 Time (min) Figure E.36. Plot of the selectivity of 2a versus reaction time using 10 mol % Ni(cod)2 and 11 mol % PCy3•HBF4 (blue filled circles) and 3 mol % Ni(cod)2 and mol % PCy3•HBF4 (blue hollow circles) at 30 °C. 459 % Yield Selectivity (E/Z) Table E.23. Yield and E/Z selectivity of 2a over time using 10 mol % Ni(cod)2 and 11 mol % PCy3•HBF4 and 3 mol % Ni(cod)2 and mol % PCy3•HBF4 at 30 °C. 10 mol % Ni(cod)2 & 11 mol % 3 mol % Ni(cod)2 & 3 mol % Time PCy3•HBF4 PCy3•HBF4 (min) E/Z Selectivity (std E/Z Selectivity (std % Yield % Yield error) error) 10 2.7±1 12.8:1 (0.2) 0.7±0.1 1:0 20 6.4±4 12.7:1 (0.1) 2±1 1:0 30 13.2±6 13.1:1 (0.4) 3±2 12:1 (2) 40 19.6±5 13.3:1 (0.5) 5±3 12:1 (2) 50 29.3±6 13.5:1 (0.2) 7±4 12:1 (1) 60 37.9±6 13.8:1 (0.8) 8±3 12:1 (2) 80 50.5±6 13.68:1 (0.02) 12±4 12:1 (1) 100 65.4±0.4 14.19:1 (0.03) 17±8 12:1 (2) 120 69.2±4 14.16:1 (0.03) 20.7±0.4 12:1 (2) 150 73.8±0.8 14.8:1 (0.5) 25±6 12:1 (2) 220 80.6 15:1 30±9 12:1 (1) c. (IPr)Ni(1,5-hexadiene) Reaction conditions and procedure were taken from literature.230 In a nitrogen-filled glovebox, (IPr)Ni(hex) (see Table E.24. below for amounts) was directly weighed into a 1-dram scintillation vial equipped with a stir bar. A stock solution of HSiPh3 in hexanes (see Table E.24. below for amounts) was prepared and distributed to the vials using a disposable 1-mL syringe. To this vial was added cyclooctane (internal standard; 8.0 μL, 0.059 mmol added to the vial) using a 25-µL syringe and additional hexanes to obtain a total reaction volume of 0.38 mL using a disposable 1- mL syringe. The vial was sealed with a septum cap, brought out of the glovebox, and the following details were performed for the corresponding experiments: • Standard reaction conditions (80 °C): the vials were heated at 80 °C on a preheated aluminum vial block for 30 min and then injected with 1a (19 µL, 0.12 mmol, 1.0 equiv) using a 25-µL syringe. • Our reaction conditions (30 °C): 1a (19 µL, 0.12 mmol, 1.0 equiv) was injected using a 25- µL syringe and the vials were heated at 30 °C on a preheated aluminum vial block. 460 The reactions were stirred at a rate of 150 rpm. Throughout the course of the reaction, 5-µL aliquots were removed with a 25-µL syringe, diluted with hexanes, and filtered into a GC vial through Celite. The filtrate was analyzed by GC to assess the reaction progress and product selectivity. Two trials were run for all experiments and the averages and standard deviations for the two trials are reported below in Table E.25. and the data is seen in Figure S25-S26. Table E.24. Amounts of (IPr)Ni(hex) and HSiPh3 for each experiment. Reaction (IPr)Nihex) HSiPh3 conditions mol % mg mmol mol % mg mmol Standard 5 3.2 0.0060 3 1.6 0.0061 (80 °C) Ours 3 1.9 0.0036 5 0.95 0.0036 (30 °C) 100 80 60 5:5 mol % (IPr)Ni(hex)/HSiPh3 40 3:3 mol % (IPr)Ni(hex)/HSiPh3 20 0 0 20 40 60 80 100 120 140 160 180 Time (min) Figure E.37. Plot of the yield of 2a versus reaction time using 5 mol % (IPr)Ni(hex) and 5 mol % HSiPh3 at 80 °C (yellow filled diamonds) and 3 mol % (IPr)Ni(hex) and 3 mol % HSiPh3 at 30 °C (yellow hollow diamonds). 461 % Yield 40 35 5:5 mol % (IPr)Ni(hex)/HSiPh3 3:3 mol % (IPr)Ni(hex)/HSiPh3 30 25 20 15 10 5 0 0 20 40 60 80 100 120 140 160 180 200 Time (min) Figure E.38. Plot of the selectivity of 2a versus reaction time using 5 mol % (IPr)Ni(hex) and 5 mol % HSiPh3 at 80 °C (yellow filled diamonds) and 3 mol % (IPr)Ni(hex) 3 mol % and HSiPh3 at 30 °C (yellow hollow diamonds). Table E.25. Yield of 2a and selectivity (E/Z) over time using 5 mol % (IPr)Ni(hex) and 5 mol % HSiPh3 at 80 °C and 3 mol % (IPr)Ni(hex) and 3 mol % HSiPh3 at 30 °C. 5 mol % (IPr)Ni(hex) & 5 mol % 3 mol % (IPr)Ni(hex) & 3 mol % Time HSiPh3 HSiPh3 (min) E/Z Selectivity (std E/Z Selectivity (std % Yield % Yield error) error) 5 1.4±0.2 1:0 -- -- 10 3.5 1:0 -- -- 16 8±2 1:0 -- -- 23 15±4 38:1 (1) 0 n.d. 30 20±7 37:1 (2) -- -- 40 32±6 37:1 (2) 0 n.d. 50 40±5 34:1 (2) -- -- 60 51±4 31:1 (2) 0 n.d. 80 69±2 23:1 (2) 0 n.d. 100 78.3±0.8 19.7:1 (0.8) 0 n.d. 120 88±2 18.1:1 (0.2) 0 n.d. 150 91.0±0.2 18.0:1 (0.4) 0 n.d. 180 94±2 18.05:1 (0.09) 0 n.d. n.d. = not determined 462 Selectivity (E/Z) d. Pd(dba)2 +P(t-Bu)3 + i-PrC(O)Cl Reaction conditions and procedure were taken from literature with slight modifications.237 In a nitrogen-filled glovebox, stock solutions of Pd(dba)2, P(t-Bu)3, and isobutyryl chloride (i- PrC(O)Cl) (see Table E.26. below for amounts) were prepared in toluene and distributed into 1- dram scintillation vials equipped with stir bars using disposable 1-mL syringes or a 100-µL syringe. To these vials were added cyclooctane (internal standard; 10 µL, 0.074 mmol) using a 25- µL syringe and additional toluene to obtain a total volume of 2.9 mL using a disposable 3-mL syringe. The vials were sealed with septum caps, brought out of the glovebox, injected with 1a (19 µL, 0.12 mmol, 1.0 equiv) using a 25-µL syringe, and heated at 30 or 80 °C on a preheated aluminum vial block. The reaction was stirred at a rate of 150 rpm. Throughout the course of the reaction, 40-µL aliquots were removed with a 50-µL syringe, diluted with hexanes, and filtered into a GC vial through Celite. The filtrate was analyzed by GC to assess the reaction progress and product selectivity. Two trials were run for all experiments and the averages and standard deviations for the two trials are reported below in Table E.27. and the data is seen in Figure E.39.- E.40. Table E.26. The catalyst loading, amount, mmol, and equiv of Pd(dba)2, P(t-Bu)3, and i- PrC(O)Cl for each catalytic trial. Reaction Pd(dba)2 P(t-Bu)3 i-PrC(O)Cl conditions mol % mg mmol mol % mg mmol mol % µL mmol Standard 0.5 0.35 6.1x10-4 0.5 0.12 5.9x10-4 0.5 0.065 6.2x10-4 (80 °C) Ours 3 2.1 3.7x10-3 3 0.74 3.7x10-3 3 0.39 3.7x10-3 (30 °C) 463 100 80 60 0.5:0.5:0.5 mol % Pd(dba)2/P(tBu)3/i-PrC(O)Cl 40 3:3:3 mol % Pd(dba)2/P(tBu)3/i-PrC(O)Cl 20 0 0 30 60 90 120 150 180 Time (min) Figure E.39. Plot of the yield of 2a versus reaction time of the formation of 2a using 0.5 mol % Pd(dba)2, 0.5 mol % P(t-Bu)3, and 0.5 mol % i-PrC(O)Cl at 80 °C (green filled triangles) and 3 mol % Pd(dba)2, 3 mol % P(t-Bu)3, and 3 mol % i-PrC(O)Cl at 30 °C (green hollow triangles). 20 15 10 5 0.5:0.5:0.5 mol % Pd(dba)2/P(tBu)3/i-PrC(O)Cl 3:3:3 mol % Pd(dba)2/P(tBu)3/i-PrC(O)Cl 0 0 30 60 90 120 150 180 Time (min) Figure E.40. Plot of the selectivity of 2a versus reaction time of the formation of 2a using 0.5 mol % Pd(dba)2, 0.5 mol % P(t-Bu)3, and 0.5 mol % i-PrC(O)Cl at 80 °C (green filled triangles) and 3 mol % Pd(dba)2, 3 mol % P(t-Bu)3, and 3 mol % i-PrC(O)Cl at 30 °C (green hollow triangles). 464 % Yield Selectivity (E/Z) Table E.27. Yield and selectivity (E/Z) of 2a over time using 0.5 mol % Pd(dba)2, 0.5 mol % P(t- Bu)3, and 0.5 mol % i-PrC(O)Cl at 80 °C and 3 mol % Pd(dba)2, 3 mol % P(t-Bu)3, and 3 mol % i-PrC(O)Cl at 30 °C. 0.5 mol % Pd(dba)2, 0.5 mol % P(t-Bu)3, and 3 mol % Pd(dba)2, 3 mol % P(t-Bu)3, and 3 0.5 mol % i-PrC(O)Cl at 80 °C mol % i-PrC(O)Cl at 30 °C E/Z Selectivity (std E/Z Selectivity Time (min) % Yield Time (min) % Yield error) (std error) 5 6±1 ..6.4:1 (1) 10 0.836±0.009 1:0 10 13±2 ….7.8:1 (0.6) 20 1.9±0.1 1:0 16 27±7 11.1:1 (2) 30 3.0±0.3 6.91:1 (0.04) 23 44±7 14.3:1 (2) 40 5±1 7.8:1 (0.5) 30 57±9 15.9:1 (2) 50 6.1±0.5 8.6:1 (0.2) 40 70±9 17.3:1 (1) 60 7±1 9.6:1 (0.5) 50 80±10 17.6:1 (1) 80 10±1 10.9:1 (0.4) 60 77±1 …18.1:1 (0.6) 100 12±1 12.341:1 (0.003) 80 82±6 …18.4:1 (0.5) 120 14.9±0.1 13.4:1 (0.2) 100 89±5 …18.4:1 (0.6) 150 18±1 15.5:1 (0.2) 120 89±8 …18.5:1 (0.8) 180 19±3 16.1:1 (0.3) 150 87±5 …18.4:1 (0.6) -- -- -- 180 82±4 …18.4:1 (0.6) -- -- -- e. Comparison of the Isomerization Catalysts Under Their Respective Reaction Conditions The data from sections E.1.12.a-d. are replicated below and combined into four plots to compare the catalysts. 465 100 80 60 40 3:5 mol % Ni[P(OEt)3]4/SZO300 5 mol % (IPr)2Ni2Cl2 20 5:5 mol % (IPr)Ni(hex)/HSiPh3 10:11 mol % Ni(cod)2/PCy3HBF4 0.5:0.5:0.5 mol % Pd(bda)2/P(tBu)3/i-PrC(O)Cl 0 0 20 40 60 80 100 120 140 160 180 Time (min) Figure E.41. Plot of the yield of 2a versus reaction time comparing the following catalytic conditions: 3 mol % Ni[P(OEt)3]4 + 5 mol % SZO300 at 30 °C (purple squares), 5 mol % (IPr)2Ni2Cl2 at 30 °C (pink rectangles), 10 mol % Ni(cod)2 + 11 mol % PCy3•HBF4 at 30 °C (blue circles), 5 mol % (IPr)Ni(hex) + 5 mol % HSiPh3 at 80 °C (yellow diamonds), and 0.5 mol % Pd(dba)2 + 0.5 mol % P(t-Bu)3 + 0.5 mol % i-PrC(O)Cl at 80 °C (green triangles). 45 40 35 30 25 20 15 3:5 mol% Ni[P(OEt)3]4/SZO300 10 5 mol % (IPr)2Ni2Cl2 5:5 mol % (IPr)Ni(hex)/HSiPh3 5 10:11 mol % Ni(cod)2/PCy3BF4 0.5:0.5:0.5 mol % Pd(dba)2/P(tBu)3/i-PrC(O)Cl 0 0 20 40 60 80 100 120 140 160 180 Time (min) Figure E.42. Plot of the selectivity of 2a versus reaction time comparing the following catalytic conditions: 3 mol % Ni[P(OEt)3]4 + 5 mol % SZO300 at 30 °C (purple squares), 5 mol % (IPr)2Ni2Cl2 at 30 °C (pink rectangles), 10 mol % Ni(cod)2 + 11 mol % PCy3•HBF4 at 30 °C (blue circles), 5 mol % (IPr)Ni(hex) + 5 mol % HSiPh3 at 80 °C (yellow diamonds), and 0.5 mol % Pd(dba)2 + 0.5 mol % P(t-Bu)3 + 0.5 mol % i-PrC(O)Cl at 80 °C (green triangles). 466 % Yield Selectivity (E/Z) f. Comparison of the Isomerization Catalysts Under our Optimized Reaction Conditions We performed time studies using 3 mol % total Ni or Pd and 3 mol % total additive/ligand at 30 °C, but we kept the respective reaction’s optimized solvent. The data from sections E.1.12.a.-d. are replicated below and combined into four plots to compare the catalysts. 100 80 3:5 mol % Ni[P(OEt3)]4/SZO300 1.5 mol % (IPr)2Ni2Cl2 60 3:3 mol % (IPr)Ni(hex)/HSiPh3 3:3 mol % Ni(cod)2/PCy3HBF4 3:3:3 mol % Pd(dba)2/P(t-Bu)3/i-PrC(O)Cl 40 20 0 0 20 40 60 80 100 120 140 160 180 Time (min) Figure E.43. Plot of the yields of 2a versus reaction time using 3 mol % Ni[P(OEt)3]4 + 5 mol % SZO300 (purple squares), 1.5 mol % (IPr)2Ni2Cl2 (dark pink rectangles), 3 mol % Ni(cod)2 + 3 mol % PCy3•HBF4 (blue circles), 3 mol % (IPr)Ni(hex) + 3 mol % HSiPh3 (yellow diamonds), and 3 mol % Pd(dba)2 + 3 mol % P(t-Bu)3 + 3 mol % i-PrC(O)Cl (green triangles) all at 30 °C. 467 % Yield 45 3:5 mol % Ni[P(OEt)3]4/SZO300 40 1.5 mol % (IPr)2Ni2Cl2 3:3 mol % (IPr)Ni(hex)/HSiPh3 35 3:3 mol % Ni(cod)2/PCy3HBF4 3:3:3 mol % Pd(dba)2/P(t-Bu)3/i-PrC(O)Cl 30 25 20 15 10 5 0 0 20 40 60 80 100 120 140 160 180 Time (min) Figure E.44. Plot of the yields of 2a versus reaction time using 3 mol % Ni[P(OEt)3]4 + 5 mol % SZO300 (purple squares), 1.5 mol % (IPr)2Ni2Cl2 (dark pink rectangles), 3 mol % Ni(cod)2 + 3 mol % PCy3•HBF4 (blue circles), 3 mol % (IPr)Ni(hex) + 3 mol % HSiPh3 (yellow diamonds), and 3 mol % Pd(dba)2 + 3 mol % P(t-Bu)3 + 3 mol % i-PrC(O)Cl (green triangles) all at 30 °C. E.1.15. Evaluation of Other Catalytic Reactions a. Hydrovinylation In a nitrogen-filled glovebox, a 1-dram vial equipped with a stir bar was charged with SZO300 (15 mg, 0.0030 mmol H+, 0.0050 equiv H+). To this vial was added a stock solution of Ni[P(OEt)3]4 (1.3 mg, 0.0018 mmol, 0.030 equiv added to each vial) and durene (internal standard; 4.1 mg, 0.031 mmol) in Et2O to obtain a total volume of 1.0 mL. The reactions were sealed with a septum cap, removed from the glovebox, injected with styrene (14.0 µL, 0.122 mmol, 2.00 equiv) using a 25-µL syringe, and placed on a pre-heated aluminum block set to 50 °C. After 15 h, the reaction was removed from the heat and opened to air, and an aliquot (~20 µL) was removed using a 25 µL syringe and filtered through a Celite plug and washed with CDCl3 (0.6 mL) directly into an NMR tube. Quantification the hydrovinylation product was determined by relative integrations between the hydrovinylation product (the doublet at 1.46 ppm, 3H) to the integration of the internal 468 Selectivity (E/Z) standard, durene (singlet at 2.18 ppm, 12H). Two trials were run for the experiment and the average and standard deviation of the yield are seen below in Table S22. Confirmation of the hydrovinylation product was obtained by scaling up this reaction (x3), filtering the reaction through a Celite plug, and concentrating to isolate the crude product (3a) to determine product selectivity by 1H NMR, which match literature values.343 The data is seen in Figure E.45. and Table E.28. Figure E.45. 1H NMR spectrum of the scaled-up hydrovinylation product 3a (top), and of the crude reaction mixture from the Ni[P(OEt)3]4/SZO300-catalyezd hydrovinylation of styrene (bottom). Both spectra recorded in CDCl3 at 25 °C. Table E.28. Integrations of durene and 3a, mmol of 3a, and the % yield of 3a. Trial ʃDurene ʃ3a 3a mmol % Yield 3a 1 12 5.98 0.061 99% 2 12 5.46 0.055 91% Average 94±6% 469 b. Hydroboration In a nitrogen-filled glovebox, a 1-dram vial equipped with a stir bar was charged with SZO300 (15 mg, 0.0030 mmol H+, 0.0050 equiv H+). To this vial was added a stock solution of Ni[P(OEt)3]4 (1.3 mg, 0.0018 mmol, 0.030 equiv added to each vial) and durene (internal standard; 5.0 mg, 0.037 mmol) in Et2O to obtain a volume of 0.50 mL. LiOt-Bu (12 mg, 0.15 mmol, 2.5 equiv) was added to the vials and the reactions were sealed with a septum cap and removed from the glovebox. On the bench, a stock solution of B2Pin2 (18 mg, 0.071 mmol, 1.2 equiv added to each vial) and N-Phenylbut-2-enamide (2u, 9.6 mg, 0.060 mmol, 1.0 equiv added to each vial) was prepared in nitrogen-sparged and dry MeOH. This stock solution was distributed to each reaction vial using a disposable 1-mL syringe to obtain a total reaction volume of 1.0 mL and the reaction was immediately placed on a pre-heated aluminum block set to 30 °C. After 18 h, an aliquot (~20 uL) was removed using a 25-µL syringe, filtered through Celite, and washed with hexanes (~1 mL) directly into a GC vial. Quantitative analysis of the formation of the hydroboration product was determined by relative integration (by GC-MS) of the product peaks against durene, in accordance with a calibration curve. Two trials were run, and the average and standard deviation of the yield are seen below in Table E.29. A control reaction was performed under identical reaction conditions in the absence of Ni[P(OEt)3]4 and SZO300. Two trials were run, and the average and standard deviation of the yield are seen below in Table E.29. Table E.29. Corresponding mmol and the % yield of 3b in the presence and absence (control) of Ni[P(OEt)3]4/SZO300. Reaction Product mmol % Yield 3b Ni[P(OEt)3]4/SZO300 0.033±0.004 55±7 control 0.0006±0.0002 0.9±0.3 After analyzing the reactions by GC-MS, the crude hydroboration reactions were combined, filtered through a Celite plug, concentrated, and purified by column chromatography (0:100 to 5:95 MeCN/DCM) to obtain the product as a white solid. This product was fully characterized, and the product selectivity was confirmed by 1H NMR. The data is seen in Figure E.46.-E.51. 470 1H NMR (500 MHz, CDCl3, 298 K): δ 7.54 (bs, 1H), 7.50 (d, J = 7.9 Hz, 2H), 7.30 (t, J = 7.9 Hz, 2H), 7.07 (t, J = 7.3 Hz, 1H), 2.49 (dd, J = 14.7, 8.4 Hz, 1H), 2.41 (dd, J = 14.7, 5.7 Hz, 1H), 1.49 (m, 1H), 1.26 (d, J = 2.4, 12H), 1.08 (d, J = 7.6 Hz, 3H). 13C{1H} NMR (126 MHz, CDCl3, 298 K): δ 171.5, 138.4, 129.1, 124.0, 119.7, 83.6, 41.5, 24.96, 24.87, 15.6 11B NMR (160 MHz, CDCl3, 298 K): δ 34.29 (s) IR (ATR, neat) v: 3239-2848 (w), 1657 (s), 1313 (s), 1141 (s), 867 (s) ASAP/HRMS (m/z): [M+] calculated for C16H24BNO3 289.1849, found 289.1868 Figure E.46. 1H NMR spectrum of N-Phenyl-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2- yl)pentanamide (3b) recorded in CDCl3 at 25 °C. 471 Figure E.47. 13C{1H} NMR spectrum of N-Phenyl-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan- 2-yl)pentanamide (3b) recorded in CDCl3 at 25 °C. Figure E.48. 11B NMR NMR spectrum of N-Phenyl-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan- 2-yl)pentanamide (3b) recorded in CDCl3 at 25 °C. 472 Figure E.49. COSY NMR spectrum of N-Phenyl-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2- yl)pentanamide (3b) recorded in CDCl3 at 25 °C. Figure E.50. HSQC NMR spectrum of N-Phenyl-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2- yl)pentanamide (3b) recorded in CDCl3 at 25 °C. 473 Figure E.51. IR spectrum of N-Phenyl-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2- yl)pentanamide (3b) recorded in CDCl3 at 25 °C. c. Hydrosilylation In a nitrogen-filled glovebox, a 1-dram vial equipped with a stir bar was charged with SZO300 (15 mg, 0.0030 mmol H+, 0.0050 equiv H+). To this was added a stock solution of Ni[P(OEt)3]4 (1.3 mg, 0.0018 mmol, 0.030 equiv added to each vial) and durene (internal standard; 4.1 mg, 0.031 mmol) in Et2O to obtain a total volume of 1.0 mL. The reactions were sealed with a septum cap, removed from the glovebox, injected with styrene (7.0 µL, 0.061 mmol, 1.0 equiv) and diphenylsilane (11 µL, 0.059 mmol, 1.0 equiv) using a 25-µL syringe, and placed on a pre-heated aluminum block set to 30 °C. After 15 h, an aliquot (~20 µL) was removed using a 25-µL syringe and filtered through a Celite plug, washed with hexanes (~1 mL) directly into a GC vial. Quantitative analysis of the formation of the hydrosilylation product was determined by relative 474 integration (by GC) of the product peaks against durene, in accordance with a calibration curve. Two trials were run, and the average and standard deviation of the yield are seen below in Table S24. Confirmation of the hydrosilylation products was obtained by concentrating the crude reaction, dissolving in CDCl3, filtering through a Celite plug directly into an NMR tube, and analyzed by 1H NMR, which match literature values.344 Table E.30. mmol, % yield, and the selectivity (l/b) of 3c from the hydrosilylation reactions. Trial Product mmol % Yield Selectivity (l/b) 1 0.014 23 1:9 2 0.011 19 1:6 average 21±3 1:7±2 Figure E.51. 1H NMR spectrum of the crude reaction of Ni[P(OEt)3]4/SZO300-catalyzed hydrosilylation reaction of diphenylsilane and styrene recorded in CDCl3 at 25 °C. 475 E.1.16. NMR and IR Spectra a. Alkene and Starting Materials Figure E.52. IR spectrum of 4-methylbenzenesulfonate-2-(2-propenyl)-phenol (1x) recorded neat at 25 °C. 476 Figure E.53. 1H NMR spectrum of 2-propen-1-yl-3-bromo-2-thiophenecarboxylate (1q) recorded in CDCl3 at 25 °C. Figure E.54. 13C{1H} NMR spectrum of 2-propen-1-yl-3-bromo-2-thiophenecarboxylate (1q) recorded in CDCl3 at 25 °C. 477 Figure E.55. COSY NMR spectrum of 2-propen-1-yl-3-bromo-2-thiophenecarboxylate (1q) recorded in CDCl3 at 25 °C. Figure E.56. 1H-13C HSQC NMR spectrum of 2-propen-1-yl-3-bromo-2-thiophenecarboxylate (1q) recorded in CDCl3 at 25 °C. 478 Figure E.57. IR spectrum of 2-propen-1-yl-3-bromo-2-thiophenecarboxylate (1q) recorded neat at 25 °C. Figure E.58. 1H NMR spectrum of 2-(3-buten-1-yl)-1-methylpyridinium iodide (S1) recorded in CDCl3 at 25 °C. 479 Figure E.59. 13C{1H} NMR spectrum of 2-(3-buten-1-yl)-1-methylpyridinium iodide (S1) recorded in CDCl3 at 25 °C. Figure E.60. COSY NMR spectrum of 2-(3-buten-1-yl)-1-methylpyridinium iodide (S1) recorded in CDCl3 at 25 °C. 480 Figure E.61. 1H-13C HSQC NMR spectrum of 2-(3-buten-1-yl)-1-methylpyridinium iodide (S1) recorded in CDCl3 at 25 °C. Figure E.62. IR spectrum of 2-(3-buten-1-yl)-1-methylpyridinium iodide (S1) recorded neat at 25 °C. 481 Figure E.63. 1H NMR spectrum of 2-(3-buten-1-yl)-1-methylpyridinium hexafluorophosphate (S2) recorded in (CD3)2CO at 25 °C. Figure E.64. 13C{1H} NMR spectrum of 2-(3-buten-1-yl)-1-methylpyridinium hexafluorophosphate (S2) recorded in (CD3)2CO at 25 °C. 482 Figure E.65. 31P{1H} NMR spectrum of 2-(3-buten-1-yl)-1-methylpyridinium hexafluorophosphate (S2) recorded in (CD3)2CO at 25 °C. Figure E.66. 19F NMR spectrum of 2-(3-buten-1-yl)-1-methylpyridinium hexafluorophosphate (S2) recorded in (CD3)2CO at 25 °C. 483 Figure E.67. COSY NMR spectrum of 2-(3-buten-1-yl)-1-methylpyridinium hexafluorophosphate (S2) recorded in (CD3)2CO at 25 °C. Figure E.68. 1H-13C HSQC NMR spectrum of 2-(3-buten-1-yl)-1-methylpyridinium hexafluorophosphate (S2) recorded in (CD3)2CO at 25 °C. 484 Figure E.69. IR spectrum of 2-(3-buten-1-yl)-1-methylpyridinium hexafluorophosphate (S2) recorded neat at 25 °C. Figure E.70. 1H NMR spectrum of allybenzene-dn (1c-dn) recorded in CDCl3 at 25 °C. 485 Figure E.71. 2H NMR spectrum of allybenzene-dn (1c-dn) recorded in 1:5 CDCl3/CHCl3 at 25 °C. a. Isomerization Products 486 Figure E.72. 1H NMR spectrum of anethole (2a) recorded in C6D6 at 25 °C. Figure E.73. 13C{1H} NMR spectrum of anethole (2a) recorded in C6D6 at 25 °C. 487 Figure E.74. 1H NMR spectrum of 1-(4-methylphenyl)-1-propene (2b) recorded in CDCl3 at 25 °C. Figure E.75. 13C{1H} NMR spectrum of 1-(4-methylphenyl)-1-propene (2b) recorded in CDCl3 at 25 °C. 488 Figure E.76. 1H NMR spectrum of β-methylstyrene (2c) recorded in C6D6 at 25 °C. Figure E.77. 13C{1H} NMR spectrum of β-methylstyrene (2c) recorded in C6D6 at 25 °C. 489 Figure E.78. 1H NMR spectrum of 1-fluoro-3-(1-propen-1-yl)benzene (2d) recorded in C6D6 at 25 °C. Figure E.79. 13C{1H} NMR spectrum of 1-fluoro-3-(1-propen-1-yl)benzene (2d) recorded in C6D6 at 25 °C. 490 Figure E.80. 19F NMR spectrum of 1-fluoro-3-(1-propen-1-yl)benzene (2d) recorded in C6D6 at 25 °C. Figure E.81. 1H NMR spectrum of 1-(4-trifluoromethylphenyl)-1-propene (2e) recorded in CDCl3 at 25 °C. 491 Figure E.82. 13C{1H} NMR spectrum of 1-(4-trifluoromethylphenyl)-1-propene (2e) recorded in CDCl3 at 25 °C. Figure E.83. 19F NMR spectrum of 1-(4-trifluoromethylphenyl)-1-propene (2e) recorded in CDCl3 at 25 °C. 492 Figure E.84. 1H NMR spectrum of isosafrole (2f) recorded in C6D6 at 25 °C. Figure E.85. 13C{1H} NMR spectrum of isosafrole (2f) recorded in C6D6 at 25 °C. 493 Figure E.86. IR spectrum of isosafrole (2f) recorded neat at 25 °C. Figure E.87. 1H NMR spectrum of 4-(1-propen-1-yl)benzaldehyde (2g) recorded in C6D6 at 25 °C. 494 Figure E.88. 13C{1H} NMR spectrum of 4-(1-propen-1-yl)benzaldehyde (2g) recorded in C6D6 at 25 °C. Figure E.89. COSY NMR spectrum of 4-(1-propen-1-yl)benzaldehyde (2g) recorded in C6D6 at 25 °C. 495 Figure E.90. 1H-13C HSQC NMR spectrum of 4-(1-propen-1-yl)benzaldehyde (2g) recorded in C6D6 at 25 °C. Figure E.91. IR spectrum of 4-(1-propen-1-yl)benzaldehyde (2g) recorded neat at 25 °C. 496 Figure E.92. 1H NMR spectrum of 1-(2-methylphenyl)-1-propene (2h) recorded in C6D6 at 25 °C. 497 Figure E.93. 13C{1H} NMR spectrum of 1-(2-methylphenyl)-1-propene (2h) recorded in C6D6 at 25 °C. Figure E.94. 1H NMR spectrum of α,β-dimethylstyrene (2i) recorded in CDCl3 at 25 °C. 498 Figure E.95. 13C{1H} NMR spectrum of α,β-dimethylstyrene (2i) recorded in CDCl3 at 25 °C. Figure E.96. 1H NMR spectrum of 1-(methoxymethoxy)-2-(1E)-1-propen-1-ylbenzene (2j) recorded in C6D6 at 25 °C. 499 Figure E.97. 13C{1H} NMR spectrum of 1-(methoxymethoxy)-2-(1E)-1-propen-1-ylbenzene (2j) recorded in C6D6 at 25 °C. Figure E.98. 13C{1H} NMR spectrum of 1-(methoxymethoxy)-2-(1E)-1-propen-1-ylbenzene (2j) recorded in CDCl3 at 25 °C. 500 Figure E.99. 1H NMR spectrum of 1-propen-1-yl-2-[(trimethylsilyl)oxy]benzene (2k) recorded in C6D6 at 25 °C. Figure E.100. 13C{1H} NMR spectrum of 1-propen-1-yl-2-[(trimethylsilyl)oxy]benzene (2k) recorded in C6D6 at 25 °C. 501 Figure E.101. 29Si{1H} NMR spectrum of 1-propen-1-yl-2-[(trimethylsilyl)oxy]benzene (2k) recorded in C6D6 at 25 °C. Figure E.102. IR spectrum of 1-propen-1-yl-2-[(trimethylsilyl)oxy]benzene (2k) recorded neat at 25 °C. 502 Figure E.103. 1H NMR spectrum of 2-(1-propenyl)phenol (2l) recorded in CDCl3 at 25 °C. Figure E.104. 13C{1H} NMR spectrum of 2-(1-propenyl)phenol (2l) recorded in CDCl3 at 25 °C. 503 Figure E.105. 1H NMR spectrum of {2-[(1E)-1-propen-1-yl]phenoxy}acetonitrile (2m) recorded in C6D6 at 25 °C. Figure E.106. 13C{1H} NMR spectrum of {2-[(1E)-1-propen-1-yl]phenoxy}acetonitrile (2m) recorded in C6D6 at 25 °C. 504 Figure E.107. COSY NMR spectrum of {2-[(1E)-1-propen-1-yl]phenoxy}acetonitrile (2m) recorded in C6D6 at 25 °C. Figure E.108. 1H-13C HSQC NMR spectrum of {2-[(1E)-1-propen-1-yl]phenoxy}acetonitrile (2m) recorded in C6D6 at 25 °C. 505 Figure E.109. 1H NMR spectrum of crotonic acid (2n) recorded in CDCl3 at 25 °C. Figure E.110. 13C{1H} NMR spectrum of crotonic acid (2n) recorded in CDCl3 at 25 °C. 506 Figure E.111. IR spectrum of crotonic acid (2n) recorded neat at 25 °C. Figure E.112. 1H NMR spectrum of 1-propen-1-yl-1H-indole (2o) recorded in C6D6 at 25 °C. 507 Figure E.113. 13C{1H} NMR spectrum of 1-propen-1-yl-1H-indole (2o) recorded in C6D6 at 25 °C. Figure E.114. 1H NMR spectrum of 2-(1-propenyl)-thiophene (2p) recorded in C6D6 at 25 °C. 508 Figure E.115. 13C{1H} NMR spectrum of 2-(1-propenyl)-thiophene (2p) recorded in C6D6 at 25 °C. Figure E.116. 1H NMR spectrum of 1-propen-1-yl-3-bromo-2-thiophenecarboxylate (2q) recorded in CDCl3 at 25 °C. 509 Figure E.117. 13C{1H} NMR spectrum of 1-propen-1-yl-3-bromo-2-thiophenecarboxylate (2q) recorded in CDCl3 at 25 °C. Figure E.118. COSY NMR spectrum of 1-propen-1-yl-3-bromo-2-thiophenecarboxylate (2q) recorded in CDCl3 at 25 °C. 510 Figure E.119. 1H-13C HSQC NMR spectrum of 1-propen-1-yl-3-bromo-2- thiophenecarboxylate (2q) recorded in CDCl3 at 25 °C. Figure E.120. IR spectrum of 1-propen-1-yl-3-bromo-2-thiophenecarboxylate (2q) recorded neat at 25 °C. 511 Figure E.121. 1H NMR spectrum of 2-sulfolene (2r) recorded in CDCl3 at 25 °C. Figure E.122. 13C{1H} NMR spectrum of 2-sulfolene (2r) recorded in CDCl3 at 25 °C. 512 Figure E.123. 1H NMR spectrum of (1-propen-1-yloxy)benzene (2s) recorded in CDCl3 at 25 °C. Figure E.124. 13C{1H} NMR spectrum of (1-propen-1-yloxy)benzene (2s) recorded in CDCl3 at 25 °C. 513 Figure E.125. 1H NMR spectrum of N-methyl-N-(prop-1-enyl)-p-toluenesulfonamide (2t) recorded in CDCl3 at 25 °C. Figure E.126. 13C{1H} NMR spectrum of N-methyl-N-(prop-1-enyl)-p-toluenesulfonamide (2t) recorded in CDCl3 at 25 °C. 514 Figure E.127. 1H NMR spectrum of N-phenyl-2-butenamide (2u) recorded in CDCl3 at 25 °C. Figure E.128. 13C{1H} NMR spectrum of N-phenyl-2-butenamide (2u) recorded in CDCl3 at 25 °C. 515 Figure E.129. IR spectrum of N-phenyl-2-butenamide (2u) recorded neat at 25 °C. Figure E.130. 1H NMR spectrum of 4,4,5,5-tetramethyl-2-1-propen-1-yl-1,3,2-dioxaborolane (2v) recorded in C6D6 at 25 °C. 516 Figure E.131. 13C{1H} NMR spectrum of 4,4,5,5-tetramethyl-2-1-propen-1-yl-1,3,2- dioxaborolane (2v) recorded in C6D6 at 25 °C. Figure E.132. 11B NMR spectrum of 4,4,5,5-tetramethyl-2-1-propen-1-yl-1,3,2-dioxaborolane (2v) recorded in C6D6 at 25 °C. 517 Figure E.133. 1H-13C NMR spectrum of 4,4,5,5-tetramethyl-2-1-propen-1-yl-1,3,2- dioxaborolane (2v) recorded in C6D6 at 25 °C. Figure E.134. IR spectrum of 4,4,5,5-tetramethyl-2-1-propen-1-yl-1,3,2-dioxaborolane (2v) recorded neat at 25 °C. 518 Figure E.135. 1H NMR spectrum of 2-(1-propen-1-yl)phenyl acetate (2w) recorded in CDCl3 at 25 °C. Figure E.136. 13C{1H} NMR spectrum of 2-(1-propen-1-yl)phenyl acetate (2w) recorded in CDCl3 at 25 °C. 519 Figure E.137. COSY NMR spectrum of 2-(1-propen-1-yl)phenyl acetate (2w) recorded in CDCl3 at 25 °C. Figure E.138. COSY NMR spectrum of 2-(1-propen-1-yl)phenyl acetate (2w) recorded in C6D6 at 25 °C. 520 Figure E.139. 1H-13C HSQC NMR spectrum of 2-(1-propen-1-yl)phenyl acetate (2w) recorded in CDCl3 at 25 °C. Figure E.140. IR spectrum of 2-(1-propen-1-yl)phenyl acetate (2w) recorded neat at 25 °C. 521 Figure E.141. 1H NMR spectrum of 1-(4-methylbenzenesulfonate)-2-(2-propen-1-yl)phenol (2x) recorded in CDCl3 at 25 °C. Figure E.142. 13C{1H} NMR spectrum of 1-(4-methylbenzenesulfonate)-2-(2-propen-1-yl)phenol (2x) recorded in CDCl3 at 25 °C. 522 Figure E.143. COSY NMR spectrum of 1-(4-methylbenzenesulfonate)-2-(2-propen-1-yl)phenol (2x) recorded in CDCl3 at 25 °C. Figure E.144. 1H-13C HSQC NMR spectrum of 1-(4-methylbenzenesulfonate)-2-(2-propen-1- yl)phenol (2x) recorded in CDCl3 at 25 °C. 523 Figure E.145. IR spectrum of 1-(4-methylbenzenesulfonate)-2-(2-propen-1-yl)phenol (2x) recorded neat at 25 °C. Figure E.146. 1H NMR spectrum of 1-bromo-4-(1-propen-1-yl)benzene (2y) recorded in CDCl3 at 25 °C. 524 Figure E.147. 13C{1H} NMR spectrum of 1-bromo-4-(1-propen-1-yl)benzene (2y) recorded in CDCl3 at 25 °C. Figure E.148. 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