Preface ........................................................ XI
List of Contributors ......................................... XIII
1 N-Heterocyclic Carbene-Ruthenium Complexes in Olefin
Metathesis .................................................. 1
Samuel Beligny and Siegfried Blechert
1.1 Introduction ................................................ 1
1.2 N-Heterocyclic Carbene-Ruthenium Complexes .................. 2
1.2.1 Introduction of N-Heterocyclic Carbenes ............... 2
1.3 Second-generation NHC-Ru Catalysts .......................... 6
1.3.1 Variations on the NHC Group ........................... 7
1.3.2 Variation on the Benzylidene Group .................... 8
1.3.3 Phosphine-free NHC-Ruthenium Complexes ................ 9
1.3.4 Variation of the Anionic Ligands ..................... 13
1.3.5 14-Electron NHC-Ruthenium Complexes .................. 13
1.4 Enantioselective Ruthenium Olefin Catalysts ................ 13
1.4.1 Grubbs II Analogues .................................. 14
1.4.2 Phosphine-free Chiral NHC-Ruthenium Complexes ........ 14
1.4.2.1 First-generation Catalysts ................... 14
1.4.2.2 Second-generation Chiral Ru Complexes ........ 15
1.5 Solid Supported NHC-Ru Complexes ........................... 16
1.5.1 Immobilization via the NHC Ligand .................... 17
1.5.2 Attachment Through the Anionic Ligand ................ 18
1.5.3 Attachment Through the Alkylidene Moiety ............. 18
1.5.4 Homogenous Catalysts ................................. 20
1.5.5 Ionic Liquids ........................................ 20
1.6 Conclusion and Outlook ..................................... 22
References ..................................................... 22
2 Ruthenium N-Heterocyclic Carbene Complexes in Organic
Transformations (Excluding Metathesis) ..................... 27
Suzanne Burling, Belinda M. Paine, and Michael K. Whittlesey
2.1 Introduction ............................................... 27
2.2 Hydrogenation and Hydrosilylation Reactions ................ 27
2.3 Isomerization .............................................. 34
2.4 Other Reactivity ........................................... 37
2.5 Tandem Reactions [29] ...................................... 42
2.5.1 Metathesis and Hydrogenation ......................... 42
2.5.2 Metathesis and Isomerization ......................... 44
2.5.3 Tandem Reactions not Involving Metathesis ............ 50
2.6 Conclusions ................................................ 51
References ..................................................... 52
3 Cross-coupling Reactions Catalyzed by Palladium
N-Heterocyclic Carbene Complexes ........................... 55
Natalie M. Scott and Steven P. Nolan
3.1 Introduction ............................................... 55
3.2 Palladium(0) NHC Complexes ................................. 56
3.3 Palladium(II) N-Heterocyclic Carbene Complexes ............. 58
3.4 Palladium/NHC Complexes as Catalysts ....................... 59
3.4.1 C-N Bond-forming Reactions: the Hartwig-Buchwald
Reaction ............................................. 59
3.4.2 C-C Bond-forming Reactions: α-Arylation of Ketones ... 63
3.4.3 Suzuki-Miyaura Cross-coupling of Aryl Chlorides
with Arylboronic Acids ............................... 64
3.4.4 C-H Bond-forming Reactions: Dehalogenation of Aryl
Halides .............................................. 67
3.4.5 C-C Bond-forming Reactions: Hydroarylation of
Alkynes .............................................. 69
3.5 Conclusion ................................................. 70
References ..................................................... 70
4 d-NHC Complexes as Catalysts in Telomerization and Aryl
Amination Reactions ........................................ 73
David J. Nielsen and Kingsley J. Cavell
4.1 Introduction ............................................... 73
4.2 Telomerization ............................................. 74
4.2.1 Definition and Background ............................ 74
4.2.1.1 Commercial Viability of the Telomerization
Reaction ..................................... 75
4.2.2 Catalyst Design: Ligand Selection .................... 76
4.2.3 Mechanism of the Pd-catalyzed Telomerization of
Buta-1,3-diene with Methanol ......................... 77
4.2.4 Pd-(NHC) Complexes as Telomerization Catalysts ....... 83
4.2.5 Telomerization in Imidazolium-based Ionic Liquids .... 90
4.3 Buchwald-Hartwig Amination Reactions Catalyzed by Pd(NHC)
Complexes .................................................. 92
4.3.1 Introduction ......................................... 92
4.3.2 Mechanism of Aryl Amination .......................... 93
4.3.3 Palladium-NHC Systems as Catalysts for Aryl
Amination ............................................ 95
4.3.3.1 Application of Preformed Pd(0/II)(NHC)
Complexes .................................... 95
4.3.3.2 In situ Pd Imidazolium Catalyst Systems ...... 98
4.4 Conclusions ............................................... 100
References .................................................... 100
5 Metal-mediated and -catalyzed Oxidations Using
N-Heterocyclic Carbene Ligands ............................ 103
Mitchell J. Schultz and Matthew S. Sigman
5.1 Introduction .............................................. 103
5.2 Metal-NHC-mediated Activation of Molecular Oxygen ......... 103
5.2.1 Co .................................................. 103
5.2.2 Ni .................................................. 105
5.2.3 Pd .................................................. 107
5.3 Metal-catalyzed Oxidations, Pd ............................ 108
5.3.1 Methane Oxidation ................................... 108
5.3.2 Alcohol Oxidation ................................... 108
5.3.3 Wacker-type Oxidations .............................. 112
5.3.4 Oxidative Carbonylation ............................. 113
5.4 Ir-catalyzed Oppenauer Oxidation of Alcohols .............. 115
5.5 Conclusion ................................................ 117
References .................................................... 117
6 Efficient and Selective Hydrosilylation of Alkenes and
Alkynes Catalyzed by Novel N-Heterocyclic Carbene Pt0
Complexes ................................................. 119
Guillaume Berthon-Celloz and István E. Markó
6.1 Introduction .............................................. 119
6.2 Initial Results ........................................... 120
6.3 Synthesis, Structure and Reactivity of (NHC)Pt(dvtms)
Complexes ................................................. 123
6.3.1 (Alkyl-NHC)Pt(dvtms) Complexes ...................... 123
6.3.2 (Aryl-NHC)Pt(dvtms) Complexes ....................... 131
6.3.3 (Benzimidazolyl-NHC)Pt(dvtms) Complexes ............. 134
6.4 Kinetic and Mechanistic Studies ........................... 137
6.5 Hydrosilylation of Alkynes ................................ 150
6.6 Summary ................................................... 158
References .................................................... 158
7 Ni-NHC Mediated Catalysis ................................ 163
Janis Louie
7.1 Introduction .............................................. 163
7.2 Rearrangement Reactions ................................... 163
7.2.1 Rearrangement Reactions of Vinyl Cyclopropanes ...... 163
7.2.2 Rearrangement Reactions of Cyclopropylen-Ynes ....... 164
7.3 Cycloaddition Reactions ................................... 167
7.3.1 Cycloaddition of Diynes and Carbon Dioxide .......... 167
7.3.2 Cycloaddition of Unsaturated Hydrocarbons and
Carbonyl Substrates ................................. 169
7.3.3 Cycloaddition of Diynes and Isocyanates ............. 170
7.3.4 Cycloaddition of Diynes and Nitriles ................ 172
7.4 Reductive Coupling Reactions .............................. 174
7.4.1 Reductive Coupling Reactions: No added Reductant .... 174
7.4.2 Reductive Coupling Reactions in the Presence of
a Reductant ......................................... 175
7.5 Oligomerization and Polymerization ........................ 178
7.6 Hydrogenation ............................................. 181
7.7 Conclusions ............................................... 181
References .................................................... 181
8 Asymmetric Catalysis with Metal N-Heterocyclic Carbene
Complexes ................................................ 183
More Mauduit and Hervé Clavier
8.1 Introduction ............................................. 183
8.2 Concept, Design and Synthesis of Chiral NHC Complexes .... 185
8.2.1 Synthesis of Ligand Precursors ..................... 185
8.2.2 Synthesis of NHC Complexes ......................... 186
8.2.3 Concept and Design of Chiral NHCs .................. 187
8.3 Asymmetric Hydrogenation ................................. 193
8.4 Asymmetric 1,4-Addition .................................. 299
8.4.1 Copper-NHC Complexes ............................... 200
8.4.2 Rhodium-NHC Complexes .............................. 203
8.4.3 Palladium-NHC Complexes ............................ 205
8.5 Asymmetric 1,2-Addition .................................. 205
8.6 Asymmetric Hydrosilylation ............................... 207
8.6.1 Rhodium-NHC Complexes .............................. 207
8.6.2 Ruthenium-NHC Complexes ............................ 211
8.7 Asymmetric Olefin Metathesis ............................. 211
8.7.1 Asymmetric Ring-closing Metathesis ................. 212
8.7.2 Asymmetric Ring-opening Metathesis/Cross
Metathesis ......................................... 213
8.8 Allylic Substitution Reaction ............................ 215
8.8.1 Palladium Catalysis ................................ 215
8.8.2 Copper Catalysis ................................... 276
8.9 Asymmetric α-Arylation ................................... 217
8.10 Palladium-catalyzed Kinetic Resolution ................... 218
8.11 Conclusion and Outlook ................................... 219
References .................................................... 220
9 Chelate and Pincer Carbene Complexes ...................... 223
Guillermina Rivera and Robert H. Crabtree
9.1 Introduction .............................................. 223
9.2 Design Strategy ........................................... 224
9.2.1 Bite Angle .......................................... 227
9.2.2 Tripod Ligands ...................................... 227
9.3 Synthetic Strategies ...................................... 228
9.4 Failure to Chelate ........................................ 231
9.5 Ligand Properties ......................................... 233
9.5.1 Types of Ligand ..................................... 234
9.5.1.1 C,C Chelates ................................ 234
9.5.1.2 N,C Chelates and Pincers .................... 234
9.5.1.3 P,C Chelates and Pincers .................... 235
9.6 Catalysis ................................................. 235
9.6.1 Medicinal Applications .............................. 236
9.7 Conclusions ............................................... 237
References .................................................... 237
10 The Quest for Longevity and Stability of Iridium-based
Hydrogenation Catalysts: N-Heterocyclic Carbenes and
Crabtree's Catalyst ...................................... 241
Leslie D. Vazquez-Serrano and Jillian M. Buriak
10.1 Introduction: Rhodium and Iridium-based Hydrogenation
Catalysts ................................................ 241
10.2 Building upon Crabtree's Catalyst with N-Heterocyclic
Carbenes ................................................. 243
10.3 Chiral Iridium N-Heterocyclic Catalysts .................. 250
10.4 Conclusions .............................................. 253
References .................................................... 253
11 Cu-, Ag-, and Au-NHC Complexes in Catalysis .............. 257
Pedro J. Pérez and M. Mar Díaz-Requejo
11.1 Introduction ............................................. 257
11.2 Copper ................................................... 258
11.2.1 Conjugate Additions ............................... 258
11.2.2 Reduction of Carbonyl Compounds ................... 261
11.2.3 Enantioselective Allylic Alkylations .............. 265
11.3 Silver ................................................... 268
11.3.1 Synthesis of 1,2-bis{Boronate) Esters ............. 268
11.3.2 NHC-Ag as Carbene Delivery Agents ................. 269
11.4 Gold ..................................................... 270
11.5 Cu-, Ag-, and Au-NHC Complexes as Catalysts for Carbene
Transfer Reactions from Ethyl Diazoacetate ............... 271
References .................................................... 274
12 N-Heterocyclic Carbenes as Organic Catalysts ............. 275
Andrew P. Dove, Russell C. Pratt, Bas G.G. Lohmeijer,
Hongbo Li, Erik C. Hagberg, Robert M. Waymouth, and
James L. Hedrick
12.1 Introduction ............................................. 275
12.2 In situ Generation of Free Carbenes ...................... 276
12.3 Small Molecule Transformations ........................... 278
12.3.1 Benzoin and Formoin Condensation .................. 278
12.3.2 Michael-Stetter Reaction .......................... 281
12.3.2.1 Stetter Reaction: Addition of Acyl
Intermediate to α,β-Unsaturated
Aldehydes ................................ 281
12.3.3 α,β-Unsaturated Aldehydes as Homoenolate
Equivalents ....................................... 283
12.3.4 Conversion of α-Substituted Aldehydes into
Esters ............................................ 284
12.3.5 Transesterification ............................... 285
12.3.6 Nucleophilic Aromatic Substitution ................ 287
12.4 Living Ring-opening Polymerization ....................... 288
12.4.1 Imidazol-2-ylidenes ............................... 289
12.4.2 Imidazolin-2-ylidenes ............................. 291
12.4.3 1,2,4-Triazol-5-ylidenes .......................... 293
12.4.4 Thiazol-2-ylidenes ................................ 294
References .................................................... 294
Subject Index ................................................. 297
|
