Description
Provides a much-needed account of the formidable "cobalt rush" in organic synthesis and catalysis
Over the past few decades, cobalt has turned into one of the most promising metals for use in catalytic reactions, with important applications in the efficient and selective synthesis of natural products, pharmaceuticals, and new materials.
Cobalt Catalysis in Organic Synthesis: Methods and Reactions provides a unique overview of cobalt-catalysed and -mediated reactions applied in modern organic synthesis. It covers a broad range of homogeneous reactions, like cobalt-catalysed hydrogenation, hydrofunctionalization, cycloaddition reactions, C-H functionalization, as well as radical and biomimetic reactions.
- First comprehensive book on this rapidly evolving research area
- Covers a broad range of homogeneous reactions, such as C-H activation, cross-coupling, synthesis of heterocyclic compounds (Pauson-Khand), and more
- Chapters on low-valent cobalt complexes as catalysts in coupling reactions, and enantioselective cobalt-catalyzed transformations are also included
- Can be used as a supplementary reader in courses of advanced organic synthesis and organometallic chemistry
Cobalt Catalysis in Organic Synthesis is an ideal book for graduates and researchers in academia and industry working in the field of synthetic organic chemistry, catalysis, organometallic chemistry, and natural product synthesis.
Table of Contents
Preface xiii
1 Introduction to Cobalt Chemistry and Catalysis 1
Marko Hapke and Gerhard Hilt
1.1 Introduction 1
1.2 Organometallic Cobalt Chemistry, Reactions, and Connections to Catalysis 4
1.2.1 Cobalt Compounds and Complexes of Oxidation States +3 to −1 4
1.2.1.1 Co(III) Compounds 5
1.2.1.2 Co(II) Compounds 5
1.2.1.3 Co(I) Compounds 7
1.2.1.4 Co(0) Compounds 8
1.2.1.5 Co(−I) Compounds 9
1.2.2 Bioorganometallic Cobalt Compounds 10
1.3 Applications in Organic Synthesis and Catalytic Transformations 12
1.4 Conclusion and Outlook 19
Abbreviations 20
References 20
2 Homogeneous Cobalt-Catalysed Hydrogenation Reactions 25
Kathrin Junge and Matthias Beller
2.1 Introduction 25
2.2 Hydrogenation of C—C Multiple Bonds (Alkenes, Alkynes) 25
2.3 Hydrogenation of Carbonyl Compounds (Ketones, Aldehydes, Carboxylic Acid Derivatives, CO2) 34
2.3.1 Ketones and Aldehydes 34
2.3.2 Carboxylic Acid Derivatives (Acids, Esters, Imides) 39
2.3.3 Hydrogenation of Carbon Dioxide 47
2.4 Hydrogenation of C—X Multiple Bonds (Imines, Nitriles) 52
2.4.1 Nitrile Hydrogenation 52
2.4.2 Imine Hydrogenation 55
2.4.3 Hydrogenation of N-Heterocycles 56
2.5 Summary and Conclusions 58
2.6 Selected Experimental Procedures 59
2.6.1 Synthesis of Cobalt Complex [(PNHPCy)Co(CH2SiMe3)]BArF4 (8a) 59
Abbreviations 60
References 61
3 Synthesis of C—C Bonds by Cobalt-Catalysed Hydrofunctionalisations 67
Daniel K. Kimand Vy M. Dong
3.1 Introduction 67
3.2 Cobalt-Catalysed C—C Bond Formations via Hydrofunctionalisation 67
3.2.1 Hydroformylation 67
3.2.2 Hydroacylation 68
3.2.3 Hydrovinylation 74
3.2.4 Hydroalkylation 78
3.2.5 Hydrocyanation 80
3.2.6 Hydrocarboxylation 81
3.3 Summary and Conclusions 83
Abbreviations 84
References 85
4 Cobalt-Catalysed C–H Functionalisation 89
Naohiko Yoshikai
4.1 Introduction 89
4.2 Low-valent Cobalt Catalysis 91
4.2.1 C–H Functionalisation with In Situ-Reduced Cobalt Catalysts 91
4.2.1.1 Hydroarylation of Alkynes and Alkenes 91
4.2.1.2 C–H Functionalisation with Electrophiles 98
4.2.1.3 C–H Functionalisation with Organometallic Reagents 103
4.2.1.4 C–H Functionalisation via 1,4-Cobalt Migration 103
4.2.1.5 Hydroacylation 103
4.2.2 C–H Functionalisation with Pincer-Type Ligands and Related Well-Defined Cobalt Catalysts 105
4.3 High-valent Cobalt Catalysis 106
4.3.1 Chelation-Assisted C–H Functionalisation with Cp*CoIII Catalysts 106
4.3.1.1 C—H Addition to Polar C=X Bonds 108
4.3.1.2 Reaction with Alkynes, Alkenes, and Allenes 111
4.3.1.3 Reaction with Formal Nitrene or Carbene Precursors 121
4.3.1.4 Reaction with E–X-type Electrophiles 126
4.3.1.5 Miscellaneous 128
4.3.2 Bidentate Chelation-Assisted C–H Functionalisation with CoIII Catalysts 130
4.3.2.1 Reaction with Alkynes, Alkenes, and Allenes 131
4.3.2.2 Dehydrogenative Cross-coupling Reactions 139
4.3.2.3 Carbonylation and Related Transformations 143
4.3.2.4 Miscellaneous Transformations 144
4.3.3 Miscellaneous 146
4.4 Summary and Outlook 146
Abbreviations 150
References 151
5 Low-valent Cobalt Complexes in C–X Coupling and Related Reactions 163
Céline Dorval and Corinne Gosmini
5.1 Introduction 163
5.2 Cobalt-Catalysed Coupling Reactions with Stoichiometric Organometallic Reagents 163
5.2.1 Cobalt-Catalysed Coupling Reactions with Grignard Reagents 163
5.2.1.1 Csp2— Csp2 Bond Formation 164
5.2.1.2 Csp2— Csp3 Bond Formation 168
5.2.1.3 Csp— Csp2 Bond Formation 173
5.2.1.4 Csp— Csp3 Bond Formation 173
5.2.1.5 Csp3— Csp3 Bond Formation 175
5.2.2 Cobalt-Catalysed Coupling Reactions with Organozinc Reagents 179
5.2.2.1 Csp— Csp2/Csp— Csp3 Bond Formation 179
5.2.2.2 Csp2— Csp2 Bond Formation 181
5.2.2.3 Csp2— Csp3 Bond Formation 183
5.2.2.4 Csp2—CN Bond Formation 186
5.2.2.5 Csp2—CO Bond Formation 186
5.2.3 Carbon–Heteroatom Bond Formation 187
5.2.3.1 C—N Bond Formation 187
5.2.3.2 C—B Bond Formation 188
5.2.4 Cobalt-Catalysed Coupling Reactions with Organoboron Reagents 188
5.3 Cobalt-Catalysed Coupling Reactions with Organomanganese Reagents 192
5.4 Cobalt-Catalysed Coupling Reactions with Copper Reagents 192
5.5 Cobalt-Catalysed Reductive Cross-coupling Reactions 193
5.5.1 Csp2—Csp2 Bond Formation 193
5.5.2 Csp2—Csp2 Bond Formation 196
5.5.3 Couplings with Benzylic Compounds 196
5.5.4 Couplings with Allylic Acetates 197
5.5.5 Csp3—Csp3 Carbon Bond Forming Reactions 197
5.6 Overview and Perspectives 199
5.7 Abbreviations 200
References 201
6 Ionic and Radical Reactions of 𝛑-Bonded Cobalt Complexes 207
Gagik G.Melikyan and Elen Artashyan
6.1 Introduction 207
6.2 Cobalt-Alkyne Complexes: Electrophilic Reactions 209
6.2.1 Intramolecular Diels–Alder Reactions 210
6.2.2 Assembling Tricyclic Ring Systems 211
6.2.3 Assembling Bicyclic Ring Systems: Decalines 212
6.2.4 Assembling Heterocyclic Ring Systems: Benzopyrans 212
6.2.5 Synthesis of Enediynes 213
6.2.6 Assembling Strained Ring Systems 213
6.2.7 Assembling Natural Carbon Skeletons 215
6.3 Cobalt–Alkyne Complexes: Radical Reactions 217
6.4 Cobalt-1,3-enyne Complexes: Electrophilic Reactions 226
6.5 Cobalt-1,3-enyne Complexes: Radical Reactions 228
6.6 Prospects 228
Abbreviations 230
References 230
7 Cobalt-Catalysed Cycloaddition Reactions 235
Gerhard Hilt
7.1 Introduction 235
7.2 Four-Membered Carbocyclic Ring Formation Reactions 235
7.2.1 [2+2] Cycloaddition of Two Alkenes 235
7.2.2 [2+2] Cycloaddition of an Alkene and an Alkyne 237
7.2.3 [2+2] Cycloaddition of Two Alkynes 238
7.3 Six-Membered Ring Formation Reactions 240
7.3.1 Cobalt-Catalysed Diels–Alder Reactions 240
7.3.2 Cobalt-Catalysed [2+2+2] Cycloaddition Reactions Other than Cyclotrimerisation of Alkynes 248
7.3.3 Cobalt-Catalysed Benzannulation Reactions 249
7.4 Synthesis of Larger Carbocyclic Ring Systems 250
7.4.1 [3+2+2] and [5+2] Cycloaddition Reaction 250
7.4.2 [6+2] Cycloaddition Reaction 251
7.5 Conclusions 253
Abbreviations 255
References 255
8 Recent Advances in the Pauson–Khand Reaction 259
David M. Lindsay and William J. Kerr
8.1 Introduction 259
8.2 Advances in the Pauson–Khand Reaction 259
8.2.1 New Methods to Promote the Pauson–Khand Reaction 259
8.2.1.1 Flow Chemistry Applications of the Pauson–Khand Reaction 260
8.2.1.2 New Promoters 261
8.2.2 Novel Substrates 264
8.2.2.1 Maleimides as Alkene Partners 264
8.2.2.2 Novel Enyne Substrates 265
8.2.2.3 Strained Reaction Partners 268
8.3 Asymmetric Pauson–Khand Reaction 269
8.4 Mechanistic and Theoretical Studies 273
8.5 Total Synthesis 276
8.5.1 Synthesis of (+)-Ingenol 276
8.5.2 Towards Retigeranic Acid A 277
8.5.3 The Total Synthesis of Astellatol 278
8.5.4 The Total Synthesis of 2-epi-𝛼-Cedrene-3-one 279
8.6 Summary and Conclusions 280
8.7 Practical Procedures for Stoichiometric and Substoichiometric Pauson–Khand Reactions 281
Abbreviations 282
References 283
9 Cobalt-Catalysed [2+2+2] Cycloadditions 287
Tim Gläsel and Marko Hapke
9.1 Introduction 287
9.2 Reaction Mechanisms of Cobalt-Catalysed Cyclotrimerisations 288
9.3 Cobalt-Based Catalysts and Catalytic Systems 292
9.4 CpCo-Based Cyclisations 296
9.4.1 Carbocyclic Compounds 296
9.4.2 Heterocyclic Compounds 298
9.5 Non-CpCo-Based Cobalt-Catalysed Cyclisations 302
9.5.1 Co2(CO)8-Mediated Cyclisations of Carbocyclic Compounds 302
9.5.2 In Situ-Generated Catalysts and Precatalysts in Carbocyclisations of Alkynes 304
9.5.3 In Situ-Generated Catalysts in the Cyclisation of Alkynes to Heterocyclic Compounds 309
9.6 Cobalt-Mediated Asymmetric [2+2+2] Cycloadditions 313
9.7 Cobalt-Mediated Cyclisations in Natural Product Synthesis 317
9.8 Novel Developments of Cobalt-Mediated Cycloaddition Catalysis 322
9.9 Summary and Outlook 326
9.10 Selected Experimental Procedures 327
9.10.1 Synthesis of [CpCo(CO)(trans-MeO2CCH=CHCO2Me)] (PCAT5) 327
9.10.2 Synthesis of [CpCo(CO){P(OEt)3}] and [CpCo(trans-MeO2CCH=CHCO2Me){P(OEt)3}] (PCAT8) 327
Abbreviations 328
References 330
10 Enantioselective Cobalt-Catalysed Transformations 337
H. Pellissier
10.1 Introduction 337
10.2 Synthesis of Chiral Acyclic Compounds Through Enantioselective Cobalt-Catalysed Reactions 338
10.2.1 Michael and (Nitro)-Aldol Reactions 338
10.2.1.1 Michael Reactions 338
10.2.1.2 (Nitro)-Aldol Reactions 342
10.2.2 Reduction Reactions 346
10.2.2.1 Reductions of Carbonyl Compounds and Derivatives 346
10.2.2.2 Reductions of Alkenes 349
10.2.3 Ring-Opening Reactions 353
10.2.3.1 Hydrolytic Ring-Openings of Epoxides 353
10.2.3.2 Ring-Openings of Epoxides by Nucleophiles Other than Water 356
10.2.4 Hydrovinylation and Hydroboration Reactions 358
10.2.4.1 Hydrovinylations 358
10.2.4.2 Hydroborations 361
10.2.5 Cross-coupling Reactions 363
10.2.6 Miscellaneous Reactions 366
10.3 Enantioselective Cobalt-Catalysed Cyclisation Reactions 370
10.3.1 [2+1] Cycloadditions 370
10.3.2 Miscellaneous Cycloadditions 379
10.3.2.1 (Hetero)-Diels–Alder Cycloadditions 379
10.3.2.2 1,3-Dipolar Cycloadditions 380
10.3.2.3 Other Cycloadditions 383
10.3.3 Cyclisations Through Domino Reactions 386
10.3.4 Miscellaneous Cyclisations 390
10.4 Conclusions 395
Abbreviations 396
References 397
11 Cobalt Radical Chemistry in Synthesis and Biomimetic Reactions (Including Vitamin B12) 417
Michał Ociepa and Dorota Gryko
11.1 Introduction 417
11.2 Cobalt-Mediated Reactions of Carbon-Centred Radicals 417
11.2.1 Homocoupling Reactions 418
11.2.2 Cross-coupling Reactions 420
11.2.3 Additions to Alkenes and Alkynes 423
11.2.4 Cyclisation Reactions 425
11.2.5 Dehalogenation 429
11.2.6 Oxidation 431
11.2.7 Acylation 433
11.2.8 Applications of Cobalt Complexes in Photoredox Catalysis 435
11.2.9 Miscellaneous Reactions 438
11.3 Cobalt-Mediated Reactions of Heteroatom-Centred Radicals 440
11.3.1 Nitrogen-Centred Radicals 440
11.3.2 Other Types of Radicals 441
11.4 Overview and Conclusion 442
11.5 Experimental Section 443
11.5.1 Synthesis of Chloro(pyridine)cobaloxime Co(dmgH)2Cl(py) (116) 443
11.5.2 Synthesis of Aqua(cyano)heptamethyl Cobyrinate (56b) – Hydrophobic Vitamin B12 Model 444
11.5.3 General Procedure for Synthesis of Co(II)(salen) and Co(III)(salen) Complexes 445
Abbreviations 445
References 446
Index 453
