Description
Organic Redox Chemistry
Explore the most recent advancements and synthesis applications in redox chemistry
Redox chemistry has emerged as a crucial research topic in synthetic method development. In Organic Redox Chemistry: Chemical, Photochemical and Electrochemical Syntheses, some key researchers in this field, including editors Dr. Frédéric W. Patureau and the late Dr. Jun-Ichi Yoshida, deliver an insightful exploration of this rapidly developing topic.
This book highlights electron transfer processes in synthesis by using different techniques to initiate them, allowing for a multi-directional perspective in organic redox chemistry. Covering a wide array of the important and recent developments in the field, Organic Redox Chemistry will earn a place in the libraries of chemists seeking a one-stop resource that compares chemical, photochemical, and electrochemical methods in organic synthesis.
Table of Contents
Biography xi
Preface xiii
1 Chemical Oxidative C—C Bond Formation 1
Koji Hirano
1.1 Introduction 1
1.2 Oxidative Aryl–Alkenyl Bond Formation 1
1.2.1 Oxidative Mizoroki–Heck Reaction with Arylmetal Reagents 2
1.2.2 Direct Oxidative Mizoroki–Heck Reaction with Arene C–Hs (Fujiwara–Moritani Reaction) 4
1.3 Oxidative Aryl–Aryl Bond Formation 8
1.3.1 Oxidative C–H/C–M Biaryl Cross-Coupling 10
1.3.2 Oxidative C–H/C–H Biaryl Cross-Coupling 12
1.4 Oxidative Aryl–Alkynyl Bond Formation 15
1.5 Oxidative C—C Bond Formation at Csp3 Center 18
1.6 Conclusion 22
References 23
2 Electrochemical Oxidative C—C Bond Formation 29
Sebastian Lips and Siegfried R. Waldvogel
2.1 Electrochemical Oxidative Aryl–Aryl Cross-Coupling Reaction 29
2.2 Electrochemical Oxidative Benzyl–Aryl Cross-Coupling Reaction 35
2.3 Electrochemical Oxidative Arylation of Olefins 36
2.4 Electrochemical Oxidative Arylation of Alkynes 39
2.5 Electrochemical Oxidative Cross-Dehydrogenative Coupling of C(sp3)—H and C(sp2)—H Bonds 39
References 39
3 Fundamentals of Photochemical Redox Reactions 45
Daniel A. Corbin, Nicholas A. Swisher, and Garret M. Miyake
3.1 Introduction: A Brief History of Photochemistry 45
3.2 Photochemistry: Background and Theory 50
3.2.1 The Electromagnetic Spectrum 50
3.2.2 Allowed and Forbidden Transitions 51
3.2.3 Photophysical Processes 52
3.2.3.1 Jablonski Diagrams 52
3.2.3.2 Absorption 53
3.2.3.3 Vibrational Relaxation 55
3.2.3.4 Internal Conversion 56
3.2.3.5 Fluorescence 56
3.2.3.6 Intersystem Crossing 57
3.2.3.7 Phosphorescence 58
3.2.4 Electron Transfers 58
3.2.4.1 Photoinduced Electron Transfer 58
3.2.4.2 Mechanisms of Electron Transfer 59
3.2.4.3 Marcus Theory 60
3.2.5 Laboratory Techniques for Studying Photoredox Processes 61
3.2.5.1 sUV–Visible Spectroscopy 61
3.2.5.2 Emission Spectroscopy 63
3.2.5.3 Transient Absorption Spectroscopy 65
3.2.5.4 Cyclic Voltammetry 67
3.2.6 Practical Considerations for Performing Photochemical Reactions 68
3.2.6.1 Factors Influencing Bimolecular Reactions 68
3.2.6.2 Photoreactor Design 68
3.2.6.3 Choice of Light Source 69
3.3 Photoredox Catalysis 69
3.3.1 General Mechanisms of Photocatalysis 69
3.3.2 Design Principles for Effective Photoredox Catalysts 70
3.3.2.1 Effective Absorption of Light 70
3.3.2.2 High Quantum Yield of Desired Excited State 71
3.3.2.3 Long-Lived Excited State 71
3.3.2.4 Favorable Thermodynamics 71
3.3.2.5 Redox Reversibility 72
3.3.3 Inorganic Photocatalysts 72
3.3.4 Organic Excited-State Oxidants 75
3.3.5 Organic Excited-State Reductants 78
3.3.6 Open-Shell Photoredox Catalysts 82
3.4 Photochemistry of Electron Donor–Acceptor Complexes 85
3.4.1 Background and Theory 85
3.4.1.1 What Is an EDA Complex? 85
3.4.1.2 How do EDA Complexes Interact with Light? 85
3.4.1.3 Electron Transfer in EDA Complexes 86
3.4.1.4 Environmental Factors Affecting EDA Complexes 86
3.4.2 Early Examples of EDA Photochemistry 87
3.4.3 Recent Examples of EDA Photochemistry 87
3.4.3.1 Rediscovering EDA Complexes through Photoredox Catalysis 87
3.4.3.2 Stoichiometric EDA Reactions 88
3.4.3.3 Use of Sacrificial Donors and Acceptors 89
3.4.3.4 Redox Auxiliaries to Expand Donor and Acceptor Scope 90
3.4.3.5 Catalytic EDA Reactions 91
3.4.3.6 Enantioselective Reactions of EDA Complexes 91
3.5 Concluding Thoughts 92
Suggested Additional Reading 92
Photochemistry and Photophysical Processes 92
Electrochemical Methods 93
Photoredox Catalysis 93
Earth Abundant Metal Photoredox Catalysis 93
EDA Complexes 93
References 93
4 C—H Bond Functionalization with Chemical Oxidants 103
Jia-Xiang Xiang, Pooja Vemuri, and Frédéric W. Patureau
4.1 Introduction 103
4.1.1 A Shift in the Rate-Determining Step 103
4.1.2 The Nature of the Oxidant 103
4.2 Metal-Based Oxidants and Other Inorganic Oxidants 104
4.2.1 Silver Salt Oxidants 105
4.2.2 Copper Salt Oxidants 108
4.2.3 Other Inorganic Oxidants 109
4.3 Organic Oxidants 109
4.3.1 Organic Peroxides 110
4.3.2 Quinones 112
4.4 Internal Oxidants (DGox) 115
4.5 Use of O2 as an Oxidant 119
4.6 Dehydrogenative Couplings with No Oxidant at All 124
4.7 Conclusion 125
References 125
5 Electrochemical Reductive Transformations 129
Mahito Atobe and Toshio Fuchigami
5.1 General Characteristics of Electrochemical Reactions 129
5.2 Mechanism of Organic Electrochemical Reductions 130
5.3 Characteristics of Organic Electrochemical Reductions 131
5.3.1 Umpolung 131
5.3.2 Selectivity 132
5.3.2.1 Chemoselectivity 133
5.3.2.2 Reaction Pathway Selectivity 133
5.3.2.3 Regioselectivity 133
5.3.2.4 Stereoselectivity 134
5.3.2.5 Selectivity Depending on Electrode Materials 134
5.4 Electroauxiliaries 135
5.4.1 Electroauxiliaries Based on Readily Electron-Transferable Functional Groups 135
5.4.2 Electroauxiliaries Based on Coordination Effects 136
5.5 Reaction Pattern of Organic Electrochemical Reductions 137
5.5.1 Transformation Type of Functional Group 137
5.5.2 Addition Type 138
5.5.3 Insertion Type 138
5.5.4 Substitution Type 139
5.5.5 Substitutive Exchange Type 139
5.5.6 Elimination Type 139
5.5.7 Dimerization Type 139
5.5.8 Crossed Dimerization 140
5.5.9 Cyclization Type 140
5.5.10 Polymorphism Formation Type 140
5.5.11 Polymerization Type 141
5.5.12 Cleavage Type 141
5.5.13 Metalation Type 141
5.5.14 Asymmetric Synthesis Type 141
5.6 Electrochemically Generated Reactive Species 141
5.6.1 Cathodically Generated Carbon Species 142
5.6.1.1 Reduction of Alkyl Halides 142
5.6.1.2 Reduction of Ketone and Imine 142
5.6.1.3 Reduction of Activated Olefin and Conjugated Olefin 142
5.6.1.4 Reduction of Active Hydrogen Compounds 143
5.6.1.5 Reduction of gem- and vic-Dihalogeno Compounds 143
5.6.2 Cathodically Generated Heteroatom Species 143
5.6.2.1 Cathodically Generated Nitrogen Species 143
5.6.2.2 Reduction of Alcohol and Carboxylic Acid 143
5.6.2.3 14-Family and 15-Family Element Species 144
5.7 Advanced Methodology for Electrochemical Reductive Transformations 144
5.7.1 Electrocatalysis for Reductive Transformations 144
5.7.1.1 Direct and Indirect Electrochemical Reductions 144
5.7.1.2 Kinds of Mediators for Reductive Transformations 145
5.7.1.3 Electrorechemical Reductive Transformations Using Mediators 146
5.7.2 Electrogenerated Bases 148
5.8 Conclusions 150
References 150
6 Electrochemical Redox-Mediated Polymer Synthesis 153
Naoki Shida and Shinsuke Inagi
6.1 Introduction 153
6.2 Synthesis of Conducting Polymers by Electrochemical Redox 154
6.2.1 Electrochemical Redox Behavior of Conducting Polymers 154
6.2.2 Oxidative Electropolymerization of Aromatic Monomers 154
6.2.3 Electrochemical Copolymer Synthesis 155
6.2.4 Reductive Electropolymerization of Aromatic Monomers 157
6.2.5 Polysilane Synthesis by Cathodic Reduction 157
6.2.6 Electropolymerization Under Nonconventional Conditions 158
6.3 Post-Functionalization of Conducting Polymers by Electrochemical Redox 159
6.3.1 Functionalization of Conducting Polymers by Anodic Substitution 159
6.3.2 Cathodic Reduction and Paired Reactions 162
6.3.3 Functionalization of Polyaniline by the CRS Method 162
6.3.4 Oxidation-Induced Intramolecular Cyclization of Conducting Polymer 163
6.3.5 Electrogenerated Transition-Metal Catalysts for Post-Functionalization 164
6.4 Synthesis of Nonconjugated Polymers by Electrochemical Redox 164
6.4.1 Electropolymerization of Electroactive Polymers 164
6.4.2 Electrochemical Redox-Controlled Polymerization 165
6.4.3 Electrochemically Induced Film Formation via Crosslinking 167
6.5 Conclusion 167
References 168
7 Chemical Paired Transformations 171
Eiji Shirakawa
7.1 Introduction 171
7.2 Direct Arylation of Arenes with Aryl Halides 173
7.3 Electron-Catalyzed Cross-Coupling Reactions of Aryl Halides 178
7.4 Conclusions 182
References 183
8 Photochemical Paired Transformations 187
Takashi Koike and Munetaka Akita
8.1 Introduction 187
8.2 Basic Concepts for Photochemical Hydrogen Atom Transfer (HAT) Process 188
8.2.1 Concept 1: Direct HAT by the Excited Photocatalyst 188
8.2.2 Concept 2: Indirect HAT Triggered by Photocatalysis 188
8.3 Asymmetric Radical Functionalization Associated with Direct HAT by Photocatalysts 189
8.3.1 Photocatalytic Functionalization of C(sp3)—H Bonds Based on Concept 1 189
8.3.2 Asymmetric Transformations Based on Concept 1 194
8.4 Asymmetric Radical Functionalization Associated with Indirect HAT Triggered by Photocatalysis 195
8.4.1 Photocatalytic Functionalization of C(sp3)—H Bonds Through 1,5-Hydrogen Atom Transfer Processes 197
8.4.2 Asymmetric Transformations Based on Concept 2 200
8.5 Summary and Outlook 201
References 202
9 Paired Electrolysis 209
Kouichi Matsumoto and Toshiki Nokami
9.1 Introduction 209
9.2 Paired Electrolysis for Sequential Reactions at both Electrodes 210
9.2.1 Using an Undivided Cell 210
9.2.2 Using a Flow Cell 211
9.3 Paired Electrolysis with Two Different Reactions at both Electrodes 213
9.3.1 Using an Undivided Cell 213
9.3.2 Using a Divided Cell 214
9.3.3 Using a Flow Cell 215
9.4 Paired Electrolysis for Generation of Two Intermediates to Afford a Final Product by the Sequential Reaction 216
9.4.1 Using an Undivided Cell 216
9.4.2 Using a Divided Cell 219
9.4.3 Using a Flow Cell 220
9.5 Conclusion 221
References 221
Index 225
