Cobalt Catalysis in Organic Synthesis

Marko Hapke is the Chair of Catalysis at the Johannes Kepler University in Linz, Austria, and also a group leader at the Leibniz Institute of Catalysis e.V. at the University of Rostock, Germany. His research centers on the development of novel cobalt catalysts for [2+2+2] cycloaddition reactions and the understanding of factors determinating reactivity and selectivity.Gerhard Hilt is Full Professor at the Carl con Ossietzky University in Oldenburg, Germany. His research interests are applications of electron-transfer-activated transition-metal complexes in organic synthesis, quantification of Lewis acidities, organic electrochemistry, and surface-assisted transformations.

• Preface xiii1 Introduction to Cobalt Chemistry and Catalysis 1Marko Hapke and Gerhard Hilt1.1 Introduction 11.2 Organometallic Cobalt Chemistry, Reactions, and Connections to Catalysis 41.2.1 Cobalt Compounds and Complexes of Oxidation States +3 to −1 41.2.1.1 Co(III) Compounds 51.2.1.2 Co(II) Compounds 51.2.1.3 Co(I) Compounds 71.2.1.4 Co(0) Compounds 81.2.1.5 Co(−I) Compounds 91.2.2 Bioorganometallic Cobalt Compounds 101.3 Applications in Organic Synthesis and Catalytic Transformations 121.4 Conclusion and Outlook 19Abbreviations 20References 202 Homogeneous Cobalt-Catalysed Hydrogenation Reactions 25Kathrin Junge and Matthias Beller2.1 Introduction 252.2 Hydrogenation of C—C Multiple Bonds (Alkenes, Alkynes) 252.3 Hydrogenation of Carbonyl Compounds (Ketones, Aldehydes, Carboxylic Acid Derivatives, CO2) 342.3.1 Ketones and Aldehydes 342.3.2 Carboxylic Acid Derivatives (Acids, Esters, Imides) 392.3.3 Hydrogenation of Carbon Dioxide 472.4 Hydrogenation of C—X Multiple Bonds (Imines, Nitriles) 522.4.1 Nitrile Hydrogenation 522.4.2 Imine Hydrogenation 552.4.3 Hydrogenation of N-Heterocycles 562.5 Summary and Conclusions 582.6 Selected Experimental Procedures 592.6.1 Synthesis of Cobalt Complex [(PNHPCy)Co(CH2SiMe3)]BArF4 (8a) 59Abbreviations 60References 613 Synthesis of C—C Bonds by Cobalt-Catalysed Hydrofunctionalisations 67Daniel K. Kimand Vy M. Dong3.1 Introduction 673.2 Cobalt-Catalysed C—C Bond Formations via Hydrofunctionalisation 673.2.1 Hydroformylation 673.2.2 Hydroacylation 683.2.3 Hydrovinylation 743.2.4 Hydroalkylation 783.2.5 Hydrocyanation 803.2.6 Hydrocarboxylation 813.3 Summary and Conclusions 83Abbreviations 84References 854 Cobalt-Catalysed C–H Functionalisation 89Naohiko Yoshikai4.1 Introduction 894.2 Low-valent Cobalt Catalysis 914.2.1 C–H Functionalisation with In Situ-Reduced Cobalt Catalysts 914.2.1.1 Hydroarylation of Alkynes and Alkenes 914.2.1.2 C–H Functionalisation with Electrophiles 984.2.1.3 C–H Functionalisation with Organometallic Reagents 1034.2.1.4 C–H Functionalisation via 1,4-Cobalt Migration 1034.2.1.5 Hydroacylation 1034.2.2 C–H Functionalisation with Pincer-Type Ligands and Related Well-Defined Cobalt Catalysts 1054.3 High-valent Cobalt Catalysis 1064.3.1 Chelation-Assisted C–H Functionalisation with Cp*CoIII Catalysts 1064.3.1.1 C—H Addition to Polar C=X Bonds 1084.3.1.2 Reaction with Alkynes, Alkenes, and Allenes 1114.3.1.3 Reaction with Formal Nitrene or Carbene Precursors 1214.3.1.4 Reaction with E–X-type Electrophiles 1264.3.1.5 Miscellaneous 1284.3.2 Bidentate Chelation-Assisted C–H Functionalisation with CoIII Catalysts 1304.3.2.1 Reaction with Alkynes, Alkenes, and Allenes 1314.3.2.2 Dehydrogenative Cross-coupling Reactions 1394.3.2.3 Carbonylation and Related Transformations 1434.3.2.4 Miscellaneous Transformations 1444.3.3 Miscellaneous 1464.4 Summary and Outlook 146Abbreviations 150References 1515 Low-valent Cobalt Complexes in C–X Coupling and Related Reactions 163Céline Dorval and Corinne Gosmini5.1 Introduction 1635.2 Cobalt-Catalysed Coupling Reactions with Stoichiometric Organometallic Reagents 1635.2.1 Cobalt-Catalysed Coupling Reactions with Grignard Reagents 1635.2.1.1 Csp2— Csp2 Bond Formation 1645.2.1.2 Csp2— Csp3 Bond Formation 1685.2.1.3 Csp— Csp2 Bond Formation 1735.2.1.4 Csp— Csp3 Bond Formation 1735.2.1.5 Csp3— Csp3 Bond Formation 1755.2.2 Cobalt-Catalysed Coupling Reactions with Organozinc Reagents 1795.2.2.1 Csp— Csp2/Csp— Csp3 Bond Formation 1795.2.2.2 Csp2— Csp2 Bond Formation 1815.2.2.3 Csp2— Csp3 Bond Formation 1835.2.2.4 Csp2—CN Bond Formation 1865.2.2.5 Csp2—CO Bond Formation 1865.2.3 Carbon–Heteroatom Bond Formation 1875.2.3.1 C—N Bond Formation 1875.2.3.2 C—B Bond Formation 1885.2.4 Cobalt-Catalysed Coupling Reactions with Organoboron Reagents 1885.3 Cobalt-Catalysed Coupling Reactions with Organomanganese Reagents 1925.4 Cobalt-Catalysed Coupling Reactions with Copper Reagents 1925.5 Cobalt-Catalysed Reductive Cross-coupling Reactions 1935.5.1 Csp2—Csp2 Bond Formation 1935.5.2 Csp2—Csp2 Bond Formation 1965.5.3 Couplings with Benzylic Compounds 1965.5.4 Couplings with Allylic Acetates 1975.5.5 Csp3—Csp3 Carbon Bond Forming Reactions 1975.6 Overview and Perspectives 1995.7 Abbreviations 200References 2016 Ionic and Radical Reactions of ;;-Bonded Cobalt Complexes 207Gagik G.Melikyan and Elen Artashyan6.1 Introduction 2076.2 Cobalt-Alkyne Complexes: Electrophilic Reactions 2096.2.1 Intramolecular Diels–Alder Reactions 2106.2.2 Assembling Tricyclic Ring Systems 2116.2.3 Assembling Bicyclic Ring Systems: Decalines 2126.2.4 Assembling Heterocyclic Ring Systems: Benzopyrans 2126.2.5 Synthesis of Enediynes 2136.2.6 Assembling Strained Ring Systems 2136.2.7 Assembling Natural Carbon Skeletons 2156.3 Cobalt–Alkyne Complexes: Radical Reactions 2176.4 Cobalt-1,3-enyne Complexes: Electrophilic Reactions 2266.5 Cobalt-1,3-enyne Complexes: Radical Reactions 2286.6 Prospects 228Abbreviations 230References 2307 Cobalt-Catalysed Cycloaddition Reactions 235Gerhard Hilt7.1 Introduction 2357.2 Four-Membered Carbocyclic Ring Formation Reactions 2357.2.1 [2+2] Cycloaddition of Two Alkenes 2357.2.2 [2+2] Cycloaddition of an Alkene and an Alkyne 2377.2.3 [2+2] Cycloaddition of Two Alkynes 2387.3 Six-Membered Ring Formation Reactions 2407.3.1 Cobalt-Catalysed Diels–Alder Reactions 2407.3.2 Cobalt-Catalysed [2+2+2] Cycloaddition Reactions Other than Cyclotrimerisation of Alkynes 2487.3.3 Cobalt-Catalysed Benzannulation Reactions 2497.4 Synthesis of Larger Carbocyclic Ring Systems 2507.4.1 [3+2+2] and [5+2] Cycloaddition Reaction 2507.4.2 [6+2] Cycloaddition Reaction 2517.5 Conclusions 253Abbreviations 255References 2558 Recent Advances in the Pauson–Khand Reaction 259David M. Lindsay and William J. Kerr8.1 Introduction 2598.2 Advances in the Pauson–Khand Reaction 2598.2.1 New Methods to Promote the Pauson–Khand Reaction 2598.2.1.1 Flow Chemistry Applications of the Pauson–Khand Reaction 2608.2.1.2 New Promoters 2618.2.2 Novel Substrates 2648.2.2.1 Maleimides as Alkene Partners 2648.2.2.2 Novel Enyne Substrates 2658.2.2.3 Strained Reaction Partners 2688.3 Asymmetric Pauson–Khand Reaction 2698.4 Mechanistic and Theoretical Studies 2738.5 Total Synthesis 2768.5.1 Synthesis of (+)-Ingenol 2768.5.2 Towards Retigeranic Acid A 2778.5.3 The Total Synthesis of Astellatol 2788.5.4 The Total Synthesis of 2-epi-;;-Cedrene-3-one 2798.6 Summary and Conclusions 2808.7 Practical Procedures for Stoichiometric and Substoichiometric Pauson–Khand Reactions 281Abbreviations 282References 2839 Cobalt-Catalysed [2+2+2] Cycloadditions 287Tim Gläsel and Marko Hapke9.1 Introduction 2879.2 Reaction Mechanisms of Cobalt-Catalysed Cyclotrimerisations 2889.3 Cobalt-Based Catalysts and Catalytic Systems 2929.4 CpCo-Based Cyclisations 2969.4.1 Carbocyclic Compounds 2969.4.2 Heterocyclic Compounds 2989.5 Non-CpCo-Based Cobalt-Catalysed Cyclisations 3029.5.1 Co2(CO)8-Mediated Cyclisations of Carbocyclic Compounds 3029.5.2 In Situ-Generated Catalysts and Precatalysts in Carbocyclisations of Alkynes 3049.5.3 In Situ-Generated Catalysts in the Cyclisation of Alkynes to Heterocyclic Compounds 3099.6 Cobalt-Mediated Asymmetric [2+2+2] Cycloadditions 3139.7 Cobalt-Mediated Cyclisations in Natural Product Synthesis 3179.8 Novel Developments of Cobalt-Mediated Cycloaddition Catalysis 3229.9 Summary and Outlook 3269.10 Selected Experimental Procedures 3279.10.1 Synthesis of [CpCo(CO)(trans-MeO2CCH=CHCO2Me)] (PCAT5) 3279.10.2 Synthesis of [CpCo(CO){P(OEt)3}] and [CpCo(trans-MeO2CCH=CHCO2Me){P(OEt)3}] (PCAT8) 327Abbreviations 328References 33010 Enantioselective Cobalt-Catalysed Transformations 337H. Pellissier10.1 Introduction 33710.2 Synthesis of Chiral Acyclic Compounds Through Enantioselective Cobalt-Catalysed Reactions 33810.2.1 Michael and (Nitro)-Aldol Reactions 33810.2.1.1 Michael Reactions 33810.2.1.2 (Nitro)-Aldol Reactions 34210.2.2 Reduction Reactions 34610.2.2.1 Reductions of Carbonyl Compounds and Derivatives 34610.2.2.2 Reductions of Alkenes 34910.2.3 Ring-Opening Reactions 35310.2.3.1 Hydrolytic Ring-Openings of Epoxides 35310.2.3.2 Ring-Openings of Epoxides by Nucleophiles Other than Water 35610.2.4 Hydrovinylation and Hydroboration Reactions 35810.2.4.1 Hydrovinylations 35810.2.4.2 Hydroborations 36110.2.5 Cross-coupling Reactions 36310.2.6 Miscellaneous Reactions 36610.3 Enantioselective Cobalt-Catalysed Cyclisation Reactions 37010.3.1 [2+1] Cycloadditions 37010.3.2 Miscellaneous Cycloadditions 37910.3.2.1 (Hetero)-Diels–Alder Cycloadditions 37910.3.2.2 1,3-Dipolar Cycloadditions 38010.3.2.3 Other Cycloadditions 38310.3.3 Cyclisations Through Domino Reactions 38610.3.4 Miscellaneous Cyclisations 39010.4 Conclusions 395Abbreviations 396References 39711 Cobalt Radical Chemistry in Synthesis and Biomimetic Reactions (Including Vitamin B12) 417Micha³ Ociepa and Dorota Gryko11.1 Introduction 41711.2 Cobalt-Mediated Reactions of Carbon-Centred Radicals 41711.2.1 Homocoupling Reactions 41811.2.2 Cross-coupling Reactions 42011.2.3 Additions to Alkenes and Alkynes 42311.2.4 Cyclisation Reactions 42511.2.5 Dehalogenation 42911.2.6 Oxidation 43111.2.7 Acylation 43311.2.8 Applications of Cobalt Complexes in Photoredox Catalysis 43511.2.9 Miscellaneous Reactions 43811.3 Cobalt-Mediated Reactions of Heteroatom-Centred Radicals 44011.3.1 Nitrogen-Centred Radicals 44011.3.2 Other Types of Radicals 44111.4 Overview and Conclusion 44211.5 Experimental Section 44311.5.1 Synthesis of Chloro(pyridine)cobaloxime Co(dmgH)2Cl(py) (116) 44311.5.2 Synthesis of Aqua(cyano)heptamethyl Cobyrinate (56b) – Hydrophobic Vitamin B12 Model 44411.5.3 General Procedure for Synthesis of Co(II)(salen) and Co(III)(salen) Complexes 445Abbreviations 445References 446Index 453