Polar Organometallic Reagents: Synthesis, Structure, Properties and Applications

Outlines recent advances in the field of polar organometallic chemistry, particularly in the context of the emergent areas of synergic and cooperative species. Polar Organometallic Reagents provides a critical overview of developments in the field of modern polar organometallic chemistry. With a particular focus on the emergent area of synergic heterometallic reagents, this timely volume describes our attempts to understand recently developed polar organometallics and their application in a range of new directions. Contributions from leading researchers present new synthetic work and discuss recent advances in characterization techniques, synthetic applications, and mechanistic understanding of heterometallic complexes. In-depth chapters provide detailed information on fundamental, structural, and theoretical aspects of polar organometallic chemistry while articulating the need and rationale for the advent of new reagents. Topics include alkali and alkaline earth organometallics, synergy and cooperativity, cationic p-block clusters and other developments in main group catalysis, synthetic trends in alkenyl copper, ate complex and borylmetal chemistry, non-traditional reaction environments, and trends in developing greener processes. Designed to keep readers updated with the latest progress in the field, this much-needed book: Includes an introductory chapter outlining the development of synergic bases and the logic behind their creation Highlights the role of solid-state structural work in elucidating the bonding and reactivity displayed by modern polar organometallics Examines the use of calculations in catalyst design and plotting more sustainable reaction pathways Discusses modern trends in solution techniques that have achieved new insights into the structures of active species Presents striking advances in the ease of handling of polar organometallics and the emergence of main group catalysis Polar Organometallic Reagents is essential reading for researchers in chemical disciplines including synthetic inorganic and coordination chemistry, main group chemistry, organometallic chemistry, organic synthesis and catalysis.

Table of Contents:
Preface xi List of Contributors xv Acknowledgements xvii 1 The Road to Aromatic Functionalization by Mixed-metal Ate Chemistry 1 Masanori Shigeno, Andrew J. Peel, Andrew E. H. Wheatley, and Yoshinori Kondo 1.1 Introduction 1 1.2 Deprotonation of Aromatics 2 1.2.1 Monometallic Bases 2 1.2.2 Bimetallic Bases 7 1.2.2.1 Group 1/1 Reagents 7 1.2.2.2 Group 1/2 Reagents 11 1.3 Aromatic Ate Complex Chemistry: Metal/Halogen Exchange 13 1.3.1 Introduction 13 1.3.2 Zincates 13 1.3.3 Cuprates 17 1.3.4 Solid-phase Synthesis 24 1.4 Deprotonation Using Ate Complexes 25 1.4.1 Introduction 25 1.4.2 Zincates 26 1.4.3 Cadmates 29 1.4.4 Aluminates 30 1.4.5 Cuprates 32 1.4.6 Argentates 39 1.5 Concluding Remarks 41 References 42 2  Structural Evidence for Synergistic Bimetallic Main Group Bases 49 Robert E. Mulvey and Stuart D. Robertson 2.1 General Introduction 49 2.2 Homometallic Bases 51 2.2.1 Carbanionic Lithium Reagents 51 2.2.2 Heavier Carbanionic Alkali Metal Reagents 56 2.2.3 Alkali Metal Amides 58 2.3 Heterometallic Bases 60 2.3.1 Heteroalkali Metal Bases 60 2.3.2 Alkali Metal Magnesiate Chemistry 64 2.3.3 Early Signs of Synergistic Behaviour in Zincate Chemistry 64 2.3.4 Lithium TMP–Zincate Chemistry 66 2.3.5 Sodium TMP–Zincate Chemistry 73 2.3.6 Lithium Chloride (Turbo Charged) TMP–Zinc Chemistry 78 2.3.7 Indirect TMP Zincation 79 2.3.8 Alkali Metal Group 13 Ates 80 2.3.9 Bimetallic Complexes Without an Alkali Metal Component 85 2.4 Outlook 91 References 91 3 Turbo Charging Group 2 Reagents for Metathesis, Metalation, and Catalysis 97 Michael S. Hill, Anne-Frédérique Pécharman, and Andrew S. S. Wilson 3.1 Introduction and Historical Context: Monometallic s-block Reagents and Their Utility 97 3.2 Heterobimetallic Reagents for Selective Metalation 100 3.2.1 Ate Complexes and Superbases 100 3.2.2 Lithium, Sodium, Potassium Magnesiates, MMgX3 101 3.2.3 Salt Effects and Magnesiate Formation 107 3.2.3.1 ‘Turbo-Grignards’ for Selective Metalation 108 3.2.3.2 Turbo–Hauser Bases 112 3.2.4 Ate Complexes of the Heavier Alkaline Earth Elements Ca, Sr, and Ba 114 3.2.4.1 Alkyl Calciate, Strontiate, and Bariate Derivatives, MM′R3 (M = Li, Na, K; M′ = Ca, Sr, Ba; R = alkyl) 115 3.2.4.2 Alkoxo and Aryloxo Calciate, Strontiate, and Bariate Derivatives, MM′ (OR/Ar)3 (M = Li, Na, K; M′ = Ca, Sr, Ba) 115 3.2.4.3 Amido Calciate, Strontiate, and Bariate Derivatives, MM′(OR/Ar)3 (M = Li, Na, K; M′ = Ca, Sr, Ba) 116 3.3 Homogeneous Catalysis by s-block Reagents 117 3.4 Outlook: Turbo Charging the Turbo Reagents and Prospects for Catalysis 120  References 121 4  Mechanisms in Heterobimetallic Reactivity: Experimental and Computational Insights for Catalyst Design in Small Molecule Activation and Polymer Synthesis 133 Frances N. Singer and Antoine Buchard 4.1 Introduction and Scope of the Chapter 133 4.2 Small Molecule Activation and Catalysis 135 4.2.1 Hydrogen Activation 135 4.2.2 Dinitrogen Activation 147 4.2.3 CO2 Activation 150 4.3 Polymerization Catalysis 152 4.3.1 Olefin polymerization 152 4.3.1.1 Metallocene-based Heterobimetallic Catalysts 154 4.3.1.2 Constrained Geometries Heterobimetallic Catalysts 159 4.3.1.3 Late Transition Metal Heterobimetallic Catalysts 164 4.3.2 Ring-opening Polymerization 171 4.3.2.1 ROP M1–O–M2 Heterobimetallic Catalysts 174 4.3.2.2 Other Heterobimetallic Catalysts for ROP 178 4.3.3 Ring-opening Copolymerization of Epoxides and Carbon Dioxide 181 4.3.3.1 Mechanistic Insight into Homobimetallic Catalysts 183 4.3.3.2 ROCOP Heterobimetallic Catalysts 186 4.4 Conclusion 192  References 193 5 Cationic Compounds of Group 13 Elements: Entry Point to the p-block for Modern Lewis Acid Reagents 201 Sanjay Singh, Mamta Bhandari, Sandeep Rawat, and Sharanappa Nembenna 5.1 Introduction 201 5.2 General Considerations 202 5.2.1 Classification of Cationic Group 13 Complexes 202 5.2.2 General Methods for the Syntheses of Cationic Group 13 Complexes 203 5.2.3 Characteristics of Counter-anions and Solvents 204 5.2.4 Quantification of LA of Cationic Group 13 Complexes 205 5.2.4.1 Experimental Methods to Quantify Lewis Acidity 206 5.2.4.2 Computational Approaches to Determine Lewis Acidity 207 5.3 Recent Developments in Cationic Group 13 Complexes 209 5.3.1 Advances in the Synthesis and Characterization of Borocations 209 5.3.1.1 Borinium Cations: Two-coordinate Cationic Boron Complexes 209 5.3.1.2 Borenium Cations: Three-coordinate Cationic Boron Complexes 211 5.3.1.3 Borenium Cations Stabilized by NHC and MIC as Neutral C-donor Ligand 212 5.3.1.4 Phosphine-coordinated Borenium Cations 217 5.3.1.5 Borenium Cations Coordinated with N-donor Ligands 218 5.3.1.6 Boronium Cations: Four-coordinate Cationic Boron Complexes 220 5.3.1.7 Miscellaneous Borocations 223 5.3.2 Advances in the Synthesis and Characterization of Aluminium Cations 223 5.3.2.1 Organoaluminium Cations 224 5.3.2.2 Aluminium Cations Supported by N,N′-donor Monoanionic Bidentate Ligands 230 5.3.2.3 An Aluminium Cationic Complex Supported by a Neutral Bidentate N,N′-donor Ligand 232 5.3.2.4 Miscellaneous Aluminium Cations that Appeared Since 2010 232 5.3.3 Advances in the Synthesis and Characterization of Heavier Group 13 (Ga, In, and Tl) Cations 235 5.3.3.1 Low Oxidation State Univalent Heavier Group 13 Cations (Ga, In, and Tl) 239 5.4 Recent Advancements in Catalytic Applications of Cationic Group 13 Complexes 241 5.4.1 Borocation in Catalysis 241 5.4.1.1 Cationic Boron Complexes in Catalysis 241 5.4.1.2 Hydroboration Reaction 241 5.4.1.3 Hydrosilylation Reaction 243 5.4.1.4 Hydrogenation Reaction 244 5.4.1.5 Use of Chiral NHC 246 5.4.1.6 Use of Chiral Borane 247 5.4.2 Cationic Al Complexes in Catalysis 248 5.4.2.1 Hydroboration Reaction 248 5.4.2.2 Cyanosilylation Reaction 250 5.4.2.3 Hydrosilylation Reaction 252 5.4.2.4 Hydroamination Reaction 254 5.4.2.5 ROP of rac-Lactide, Epoxides and ε-Caprolactone 255 5.4.3 Cationic Heavier Group 13 Complexes in Catalysis 256 5.4.3.1 Cationic Gallium Complexes in Catalysis 256 5.4.3.2 Activation of Alcohols 257 5.4.3.3 Olefin Epoxidation in Water 257 5.4.3.4 Transfer Hydrogenation of Alkene 258 5.4.3.5 Hydroarylation Reaction 258 5.4.3.6 Cycloisomerization of Enyne 260 5.4.3.7 Tandem Carbonyl–Olefin Metathesis 260 5.4.3.8 Polymerization of Propylene Oxide and Isobutylene 261 5.4.3.9 Cationic Indium and Thallium Complexes in Catalysis 262 5.4.3.10 Coupling of Epoxides and Lactones 262 5.4.3.11 ROP of Epoxides, Lactide, and ε-Caprolactone 262 5.5 Concluding Remarks 264 References 265 6 Recent Development in the Solution Structural Chemistry of Main Group Organometallics 271 Alistair M. Broughton, Leonie J. Bole, Andrew E. H. Wheatley, and Eva Hevia 6.1 Introduction 271 6.2 Monometallic Systems 273 6.2.1 Introduction 273 6.2.2 Organo(s-block Metal) Aggregation and Reactivity 273 6.2.3 DOSY on s-block Organometallics 280 6.2.3.1 Development and Early Applications 280 6.2.3.2 Recent Refinements to Diffusion Techniques 283 6.3 Heteropolymetallic Systems 287 6.3.1 Introduction 287 6.3.2 s/s-block Systems 287 6.3.2.1 Alkali Metal/Magnesium 287 6.3.2.2 Turbo–Hauser Chemistry 289 6.3.3 s/p-block Systems 291 6.3.3.1 Lithium/Aluminium Chemistry and Trans-metal-trapping 291 6.3.3.2 Alkali Metal/Gallium Systems 293 6.3.4 s/d-block Systems 294 6.3.4.1 Lithium/Cadmium 294 6.3.4.2 Lithium/Copper 295 6.3.4.3 Alkali Metal/Zinc 302 6.3.4.4 Magnesium/Zinc 308 6.4 Concluding Remarks 311 References 312 7 Chemistry of Boryl Anions: Recent Developments 317 Makoto Yamashita 7.1 Introduction 317 7.2 Boryl Anions as a Salt of Alkali Metals 317 7.2.1 Early Examples of Base-stabilized Boryl Anions and Borylcopper Species 317 7.2.2 Diaminoboryl Anions as a Lithium Salt 318 7.2.3 Base-stabilized Boryl Anion with π-delocalization 321 7.2.3.1 Lewis Base-stabilized Borole Anion 321 7.2.3.2 Carbene-stabilized Boryl Anion 322 7.2.3.3 Stabilization with Cyanide 323 7.2.3.4 Metal-substituted Boryl Anion 325 7.3 Boryl Anions as a Salt of Magnesium, Zinc, and Copper as Relatives of Carbanions 325 7.3.1 Transmetalation of Boryllithium to Magnesium, Copper, and Zinc to Form Borylmetals 325 7.3.2 Transmetalation of Diborane(4) to Magnesium and Zinc to Form Borylmetals 329 7.4 Application of Borylcopper and Borylzinc Species for Synthetic Organic Chemistry 330 7.5 Summary 332 References 333 8 Novel Chemical Transformations in Organic Synthesis with Ate Complexes 337 Keiichi Hirano and Masanobu Uchiyama 8.1 Introduction 337 8.2 Ate Complexes 337 8.3 Di-anion-type Zincate 338 8.3.1 Mono-anion-type Zincates and Di-anion-type Zincates 338 8.3.2 Highly Bulky Di-anion-type Zincate: Li2[Znt-Bu4] 339 8.3.2.1 Halogen–Zinc Exchange in the Presence of Proton Sources 339 8.3.2.2 Anionic Polymerization in Water 340 8.3.3 Cross-coupling Reaction via C–O Bond Cleavage 340 8.4 Heteroleptic Zinc Ate Complexes 342 8.4.1 Deprotonative Metalation of Aromatic C–H Bonds 342 8.4.1.1 Amidozincate Base: Li[(TMP)ZnR2] 343 8.4.1.2 Amidoaluminate Base: Li[(TMP)Ali-Bu3] 343 8.4.1.3 Amidocuprate Base: Li2[(TMP)Cu(CN)R] 345 8.4.2 Hydridozincate: M[HZnMe2] 346 8.4.3 Silylzincates 348 8.4.3.1 Silylzincation of Alkynes 349 8.4.3.2 Silylzincation of Alkynes via Si–B Activation 350 8.4.3.3 Silylzincation of Alkenes (1): Synthesis of Allylsilanes 350 8.4.3.4 Silylzincation of Alkenes (2): Synthesis of Alkylsilanes 350 8.4.4 Perfluoroalkylzincates Li[RFZnMeCl] and RFZnR 350 8.4.5 Design of Boryl Anion Equivalents and Applications in Synthetic Chemistry 354 8.4.5.1 Borylzincate: M[(pinB)ZnEt2] 355 8.4.5.2 Trans-Diboration of Alkynes via pseudo-Intramolecular Activation 357 8.4.5.3 Trans-Alkynylboration of Alkynes 360 8.5 Conclusion 360 References 362 9  Isolable Alkenylcopper Compounds: Synthesis, Structure, and Reaction Chemistry 365 Liang Liu, Chao Wang, and Zhenfeng Xi 9.1 Introduction 365 9.2 Well-defined Alkenylcopper Compounds 365 9.2.1 Mono-alkenyl Organocopper Compounds with Intramolecular Coordination 366 9.2.2 Mono-alkenyl Organocopper Compounds Stabilized by N-heterocyclic Carbene 367 9.2.3 Butadienyl Copper Compounds 369 9.3 Summary 379 References 380 Index 383

About the Author :
Andrew Wheatley, Professor of Materials Chemistry, Yusuf Hamied Department of Chemistry, University of Cambridge, UK. His research is focused on understanding the structure, synthesis and reactivity of mixed-metal organometallics, catalysts and composite materials. Masanobu Uchiyama, Professor, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Japan, and Professor, Research Initiative for Supra-Materials (RISM) at Shinshu University, Japan (Cross Appointment). His research interests include development of innovative synthetic processes, new materials, and new functions based on integration of theoretical calculations and elements chemistry.