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And Nickel(Allyl) A Dissertation entitled Hydroamination and Hydrosilylation Catalyzed by Cationic Palladium- and Nickel(allyl) Complexes Supported by 3-Iminophosphine Ligands by Hosein Tafazolian Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Doctor of Philosophy Degree in Chemistry _________________________________________ Dr. Joseph A. R. Schmidt, Committee Chair _________________________________________ Dr. Mark R. Mason, Committee Member _________________________________________ Dr. Steven J. Sucheck, Committee Member _________________________________________ Dr. John-David T. Smith, Committee Member _________________________________________ Dr. Amanda Bryant-Friedrich, Dean College of Graduate Studies The University of Toledo December 2016 Copyright 2016, Hosein Tafazolian This document is copyrighted material. Under copyright law, no parts of this document may be reproduced without the expressed permission of the author. An Abstract of Hydroamination and Hydrosilylation Catalyzed by Cationic Palladium- and Nickel(allyl) Complexes Supported by 3-Iminophosphine Ligands by Hosein Tafazolian Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Doctor of Philosophy Degree in Chemistry The University of Toledo December 2016 Chapter 1. A brief introduction to organometallic chemistry and catalysis is presented to explain the basics of the field to the reader. A few examples of catalysis, mainly hydroamination and hydrosilylation, and their mechanisms are presented. The significance of ligands in catalysis is also discussed. Chapter 2. Six new 3-iminophosphine ligands and their cationic (allyl)palladium complexes were synthesized. These catalytically active palladium complexes were utilized in the hydroamination of cyclohexylallene with secondary amines in order to better understand the mechanism of this hydroamination reaction. The kinetics of the reaction were also studied with the help of time-resolved 1H NMR spectroscopy, as well as deuterium labeling experiments. Chapter 3. Four new [(3-iminophosphine)nickel(allyl)]OTf complexes were synthesized and characterized by NMR spectroscopy, elemental analysis, and X-ray crystallography. Equimolar reactions of these new complexes with secondary amines provided useful information on the activation of these complexes in the presence of secondary amines. They also catalyzed the hydroamination of terminal allenes with iii secondary amines to produce allylamines in moderate to high yields, which were then characterized by 1H and 13C NMR spectroscopy and high resolution mass spectrometry. Chapter 4. A previously synthesized [(3-iminophosphine)palladium(allyl)]OTf complex was found to be an efficient catalyst for the hydrosilylation of allenes with a wide range of hydrosilanes. Several new allyl- and vinylsilanes were synthesized catalytically and fully characterized. The observed regioselectivity and a double labeled H/D experiment resolved the mechanism of the reaction while also explaining its regioselectivity. Chapter 5. Various cationic palladium and nickel complexes were investigated in the hydrosilylation of imines, ketones, and alkynes. Several new allylamine, silylether and vinylsilane compounds were formed in this study and characterized. Substrate scope and mechanisms of the catalytic reactions are discussed. iv Dedicated to My Family and Friends Table of Contents Abstract .............................................................................................................................. iii Dedication ............................................................................................................................v Table of Contents ............................................................................................................... vi List of Tables ................................................................................................................... viii List of Figures .................................................................................................................... ix List of Schemes ....................................................................................................................x 1 Introduction to Organometallic Chemistry and Catalysis ........................................1 1.1 Organometallic Chemistry ................................................................................1 1.2 Catalysis ............................................................................................................3 1.3 Hydroamination and Hydrosilylation ...............................................................6 1.4 Significance of Ligands in Catalysis ...............................................................13 1.5 Hemilabile Ligands .........................................................................................15 1.6 Conclusion ......................................................................................................17 2 The Electronic Role of 3-Iminophosphine Ligands in Palladium-Catalyzed Intermolecular Hydroamination .............................................................................18 2.1 Introduction .....................................................................................................18 2.2 Results and Discussion ...................................................................................21 2.3 Experimental Section ......................................................................................34 2.4 Conclusion ......................................................................................................48 vi 3 Synthesis of [(3-Iminophosphine)nickel(allyl)]OTf Complexes and Their Catalytic Activity for the Hydroamination of Allenes ...........................................49 3.1 Introduction .....................................................................................................49 3.2 Results and Discussion ...................................................................................51 3.3 Experimental Section ......................................................................................62 3.4: Conclusion ......................................................................................................86 4 Efficient Regioselective Allene Hydrosilylation Catalyzed by a [(3- Iminophosphine)Pd(allyl)]OTf Precatalyst ............................................................87 4.1 Introduction .....................................................................................................87 4.2 Results and Discussion ...................................................................................89 4.3 Experimental Section ......................................................................................97 4.4 Conclusion ....................................................................................................107 5 Catalytic Hydrosilylation of Imines, Ketones, and Alkynes Utilizing Cationic 3- Iminophosphine Complexes of Palladium and Nickel.........................................109 5.1 Introduction ...................................................................................................109 5.2 Results and Discussion .................................................................................111 5.3 Experimental Section ....................................................................................134 5.4 Conclusion ....................................................................................................166 References ........................................................................................................................168 vii List of Tables 1 Hammett constants and reaction yields of [(3IP)Pd(allyl)]OTf precatalysts .........23 2 Cationic [(3IP)Ni(allyl)]+ complexes .....................................................................52 3 Hydroamination of cyclohexylallene catalyzed by 4b ...........................................56 4 Hydroamination of nhexyl-, nbutyl- and benzylallene catalyzed by 4b .................58 5 Hydroamination of 1,1-dimethylallene catalyzed by 4b........................................61 6 Optimization of catalytic hydroamination .............................................................66 7 Crystallographic data for compound 4b ................................................................85 8 Catalytic hydrosilylation of cyclohexylallene .......................................................91 9 Catalytic hydrosilylation of dimethylallene ...........................................................93 10 Effect of reaction temperature .............................................................................112 11 Pd-catalyzed reduction of allylimines ..................................................................113 12 Investigation of ketimines ....................................................................................118 13 Hydrosilylation of alkynes with silanes catalyzed by 15a ...................................121 14 Catalytic activity of 15a and 4a in the hydrosilylation ........................................128 15 Hydrosilylation of ketones with diphenylsilane catalyzed by 4a ........................129 16 Substrate scope of alkyne hydrosilylation catalyzed by 4a .................................133 17 Crystallographic data for compound 4a ...............................................................166 viii List of Figures 1 Square planar Zeise’s salt ........................................................................................1
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