Science of Synthesis Knowledge Updates 2012 Vol. 3 (eBook)

Jeffrey W. Bode, Dennis Hall, Norbert Krause, Jie Jack Li, Bernd Plietker, Ernst Schaumann (Herausgeber)

eBook Download: EPUB

2014 | 1. Auflage
592 Seiten
Thieme (Verlag)
978-3-13-178851-1 (ISBN)

Infos

Science of Synthesis is a reference work for preparative methods in synthetic chemistry. Its product-based classification system enables chemists to easily find solutions to their synthetic problems.

Key Features:

• Critical selection of reliable synthetic methods, saving the researcher the time required to find procedures in the primary literature.
• Expertise provided by leading chemists.
• Detailed experimental procedures.
• The information is highly organized in a logical format to allow easy access to the relevant information.

The Science of Synthesis Editorial Board, together with the volume editors and authors, is constantly reviewing the whole field of synthetic organic chemistry as presented in Science of Synthesis and evaluating significant developments in synthetic methodology. Four annual volumes updating content across all categories ensure that you always have access to state-of-the-art synthetic methodology.

Inhalt

Science of Synthesis: Knowledge Updates 2012/3 1
Title page 5
Imprint 7
Preface 8
Abstracts 10
Overview 18
Table of Contents 20
Volume 1: Compounds with Transition Metal--Carbon p-Bonds and Compounds of Groups 10–8 (Ni, Pd, Pt, Co, Rh, Ir, Fe, Ru, Os) 36
1.4 Product Class 4: Organometallic Complexes of Cobalt 36
1.4.5 Organometallic Complexes of Cobalt 36
1.4.5.1 Cobalt–.5-Dienyl Complexes 36
1.4.5.1.1 Synthesis of Cobalt–.5-Dienyl Complexes 36
1.4.5.1.1.1 Method 1: Synthesis of Chiral Dicarbonyl(.5-cyclopentadienyl)cobalt(I) and (.5-Cyclopentadienyl)(.4-diene)cobalt(I) Complexes 36
1.4.5.1.1.1.1 Variation 1: Synthesis of Chiral Dicarbonyl(.5-cyclopentadienyl)cobalt(I) Complexes by Oxidative Addition 37
1.4.5.1.1.1.2 Variation 2: Synthesis of Chiral (.5-Cyclopentadienyl)(.4-diene)cobalt(I) Complexes by Substitution of Ligands 37
1.4.5.1.1.2 Method 2: Synthesis of (Alkene)carbonyl(.5-cyclopentadienyl)cobalt(I) Complexes via Displacement of One Carbonyl Moiety 39
1.4.5.1.1.3 Method 3: Synthesis of (.5-Cyclopentadienyl)(.4-diene)cobalt(I) Complexes via Substitution of Ligands 40
1.4.5.1.1.4 Method 4: Synthesis of (.5-Cyclopentadienyl)cobalt–N-Heterocyclic Carbene Complexes by Exchange of Ligands 40
1.4.5.1.1.4.1 Variation 1: Synthesis of Carbonyl(.5-cyclopentadienyl)cobalt–N-Heterocyclic Carbene Complexes 41
1.4.5.1.1.4.2 Variation 2: Synthesis of (.5-Cyclopentadienyl)(ethene)cobalt–N-Heterocyclic Carbene Complexes 42
1.4.5.1.1.4.3 Variation 3: Synthesis of (.5-Cyclopentadienyl)(triphenylphosphine)cobalt–N-Heterocyclic Carbene Complexes 42
1.4.5.1.1.5 Method 5: Synthesis of (.5-Cyclopentadienyl)(phosphine)cobalt(I)–Ligand Complexes 43
1.4.5.1.1.5.1 Variation 1: Synthesis of Carbonyl(.5-cyclopentadienyl)(triphenylphosphine)cobalt(I) 43
1.4.5.1.1.5.2 Variation 2: Synthesis of (.5-Cyclopentadienyl)(triphenylphosphine)cobalt(I)–Alkene Complexes 43
1.4.5.1.1.5.3 Variation 3: Synthesis of {[2-(Di-tert-butylphosphino)ethyl]cyclopentadienyl}(ethene)cobalt(I) 44
1.4.5.1.1.6 Method 6: Synthesis of (.5-Cyclopentadienyl)cobalt–Dinitrosoalkane Complexes 45
1.4.5.1.1.7 Method 7: Synthesis of (.5-Pentamethylcyclopentadienyl)cobalt–.3-Allyl Complexes by Exchange of Ligands 46
1.4.5.1.1.8 Method 8: Synthesis of (.5-Cyclopentadienyl)cobalt–.5-Pentadienyl Complexes by Exchange of Ligands 48
1.4.5.1.1.9 Method 9: Synthesis of (.5-Cyclopentadienyl)cobalt–Alkyne Complexes 50
1.4.5.1.1.10 Method 10: Synthesis of (.5-Cyclopentadienyl)cobaltacycles 51
1.4.5.1.1.10.1 Variation 1: Synthesis of (.5-Cyclopentadienyl)cobaltacyclobutenes 51
1.4.5.1.1.10.2 Variation 2: Synthesis of (.5-Cyclopentadienyl)cobaltasilacyclopentenes 51
1.4.5.1.2 Applications of Cobalt–.5-Dienyl Complexes in Organic Synthesis 52
1.4.5.1.2.1 Method 1: Inter- and Intramolecular [2 + 2 + 2] Cyclizations 52
1.4.5.1.2.1.1 Variation 1: Inter- and Intramolecular [2 + 2 + 2] Cyclizations of Triynes in Aromatic and Aqueous Solvents 52
1.4.5.1.2.1.2 Variation 2: Intermolecular [2 + 2 + 2] Cyclizations of Diynes and Nitriles: Preparation of Pyridines 59
1.4.5.1.2.1.3 Variation 3: Intermolecular [2 + 2 + 2] Cyclizations of Enediynes and Allenediynes 63
1.4.5.1.2.1.4 Variation 4: Inter- and Intramolecular [2 + 2 + 2] Cyclizations of Diynes with Heteroatom-Substituted Multiple Bonds 67
1.4.5.1.2.2 Method 2: Other Cyclizations 67
1.4.5.1.2.2.1 Variation 1: [2 + 2] Cycloaddition 68
1.4.5.1.2.2.2 Variation 2: [3 + 2] Annulation 69
1.4.5.1.2.2.3 Variation 3: [3 + 2 + 2] Cycloaddition 70
1.4.5.1.2.2.4 Variation 4: [5 + 2] Cycloaddition 72
1.4.5.1.2.3 Method 3: Miscellaneous Reactions 73
1.4.5.1.2.3.1 Variation 1: Cobalt-Mediated Ring Expansion 73
1.4.5.1.2.3.2 Variation 2: Linear Co-oligomerization of Alkynes with Alkenes 74
1.4.5.1.2.3.3 Variation 3: Hydroamination of Alkynes 76
1.4.5.1.2.3.4 Variation 4: Activation of sp3 C--H Bonds 77
1.4.5.1.2.3.5 Variation 5: Vinylic C--H Functionalization Reactions 78
1.4.5.2 Miscellaneous Cobalt Complexes 79
1.4.5.2.1 Synthesis of Miscellaneous Cobalt Complexes 79
1.4.5.2.1.1 Method 1: Synthesis of Methyltetrakis(trimethylphosphine)cobalt(I) 79
1.4.5.2.1.2 Method 2: Synthesis of Chlorotris(trimethylphosphine)cobalt(I) 80
1.4.5.2.1.3 Method 3: Synthesis of Dihalobis(phosphine)cobalt(II) Complexes 80
1.4.5.2.1.4 Method 4: Cobalt(II) or -(III) Salts as Precatalysts 81
1.4.5.2.1.5 Method 5: Preformed Cobalt(II) and Cobalt(III) Complexes 82
1.4.5.2.2 Applications of Miscellaneous Cobalt Complexes in Organic Synthesis 83
1.4.5.2.2.1 Method 1: Cobalt-Catalyzed Homocoupling Reactions 83
1.4.5.2.2.2 Method 2: C(sp2)--C(sp2) Cross-Coupling Reactions 84
1.4.5.2.2.2.1 Variation 1: Alkenylation 85
1.4.5.2.2.2.2 Variation 2: Biaryl Formation 86
1.4.5.2.2.3 Method 3: C(sp2)--C(sp3) Cross-Coupling Reactions 88
1.4.5.2.2.3.1 Variation 1: Alkylation of Alkenyl Halides 88
1.4.5.2.2.3.2 Variation 2: Alkenylation of Alkyl Halides 89
1.4.5.2.2.3.3 Variation 3: Alkylation of Aromatic Halides 90
1.4.5.2.2.3.4 Variation 4: Arylation of Alkyl Halides 90
1.4.5.2.2.3.5 Variation 5: Pseudodirect and Direct Arylation of Alkyl Halides 92
1.4.5.2.2.3.6 Variation 6: Allylation 94
1.4.5.2.2.4 Method 4: C(sp3)--C(sp3) Cross-Coupling Reactions 95
1.4.5.2.2.4.1 Variation 1: Allylation 95
1.4.5.2.2.4.2 Variation 2: Benzylation 96
1.4.5.2.2.4.3 Variation 3: Alkylation 96
1.4.5.2.2.5 Method 5: Alkynylation 97
1.4.5.2.2.5.1 Variation 1: Benzylation of Alkynes 97
1.4.5.2.2.5.2 Variation 2: Alkylation of Alkynes 97
1.4.5.2.2.5.3 Variation 3: Alkenylation of Alkynes 98
1.4.5.2.2.6 Method 6: Acylation 98
1.4.5.2.2.7 Method 7: Radical Reactions 99
1.4.5.2.2.8 Method 8: Cross Coupling of Unsaturated Compounds 101
1.4.5.2.2.8.1 Variation 1: Alkyne Functionalization 101
1.4.5.2.2.8.2 Variation 2: Cross Coupling of Alkynes with Enones 101
1.4.5.2.2.8.3 Variation 3: Cross-Coupling Reactions Involving Alkenes and Alkynes 103
1.4.5.2.2.9 Method 9: Michael-Type Conjugate Additions 103
1.4.5.2.2.10 Method 10: Formation of Carbon--Heteroatom Bonds 104
1.4.5.2.2.11 Method 11: Cross-Coupling Reactions with Carbonyl Compounds 105
1.4.5.2.2.11.1 Variation 1: Allylation 105
1.4.5.2.2.11.2 Variation 2: Formation of Hydroxy Amides and Esters 106
1.4.5.2.2.11.3 Variation 3: Arylation 106
1.4.5.2.2.12 Method 12: Multicomponent Reactions 107
1.4.5.2.2.13 Method 13: Preparation of Organometallic Derivatives 108
1.4.5.2.2.14 Method 14: Cyclization Reactions 109
1.4.5.2.2.15 Method 15: Cobalt-Catalyzed Cycloadditions 110
1.4.5.2.2.15.1 Variation 1: [2 + 2] Cycloadditions 110
1.4.5.2.2.15.2 Variation 2: [3 + 2] Cycloadditions 111
1.4.5.2.2.15.3 Variation 3: [4 + 2] Cycloadditions 112
1.4.5.2.2.15.4 Variation 4: Homo-Diels–Alder Reactions 115
1.4.5.2.2.15.5 Variation 5: [6 + 2] Cycloadditions 116
1.4.5.2.2.15.6 Variation 6: [2 + 2 + 2] Cycloadditions 116
1.4.5.2.2.15.7 Variation 7: [4 + 2 + 2] Cycloadditions 120
1.4.5.2.2.15.8 Variation 8: [6 + 4] Cycloadditions 121
1.4.5.2.2.15.9 Variation 9: Dipolar Cycloadditions with Nitrones 122
1.4.5.2.2.16 Method 16: Alkene Functionalizations 123
1.4.5.2.2.16.1 Variation 1: Cyclopropanation 123
1.4.5.2.2.16.2 Variation 2: Aziridination 127
1.4.5.2.2.16.3 Variation 3: Hydrovinylation of Alkenes 129
1.4.5.2.2.16.4 Variation 4: Miscellaneous Alkene Functionalizations 130
1.4.5.2.2.17 Method 17: C--H Activation 131
1.4.5.2.2.17.1 Variation 1: Cobalt-Catalyzed Assisted ortho-Functionalization 131
1.4.5.2.2.17.2 Variation 2: Cobalt-Catalyzed Direct Arylation 134
1.4.5.2.2.17.3 Variation 3: Cobalt-Catalyzed Transformation of Alkynyl C--H Bonds 135
1.4.5.2.2.17.4 Variation 4: Cobalt-Catalyzed C--H Amination 135
1.4.5.2.2.17.5 Variation 5: Formation of Organocobalt Complexes 136
1.4.5.2.2.18 Method 18: Cobalt-Catalyzed Ring-Expansion and Ring-Opening Reactions 141
1.4.5.2.2.18.1 Variation 1: Cobalt-Catalyzed Carboxylative and Carbonylative Ring Expansion/Opening 142
1.4.5.2.2.18.2 Variation 2: Cobalt-Catalyzed Ring-Opening Reactions 144
Volume 3: Compounds of Groups 12 and 11 (Zn, Cd, Hg, Cu, Ag, Au) 158
3.6 Product Class 6: Organometallic Complexes of Gold 158
3.6.14 Organometallic Complexes of Gold (Update 1) 158
3.6.14.1 Asymmetric Gold-Catalyzed Transformations 158
3.6.14.1.1 Asymmetric Gold(I)-Catalyzed Transformations Proceeding via Initial Alkyne p-Activation 163
3.6.14.1.1.1 Cycloisomerization Reactions 163
3.6.14.1.1.1.1 Method 1: Cycloisomerizations of 1,6-Enynes 163
3.6.14.1.1.1.1.1 Variation 1: 5-exo-dig Cyclization 163
3.6.14.1.1.1.1.2 Variation 2: 6-endo-dig Cyclization 166
3.6.14.1.1.1.2 Method 2: Cycloisomerizations of 1,5-Enynes 170
3.6.14.1.1.1.3 Method 3: Cyclizations of 1,3-Enynes 171
3.6.14.1.1.1.4 Method 4: Cyclopropanations 172
3.6.14.1.1.1.4.1 Variation 1: Intermolecular Cyclopropanation 172
3.6.14.1.1.1.4.2 Variation 2: Intramolecular Cyclopropanation 174
3.6.14.1.1.1.5 Method 5: Analogous Cycloisomerizations Proceeding through Gold(I) Carbenoids 175
3.6.14.1.1.1.6 Method 6: Other Cycloisomerization Reactions of Propargyl Carboxylates 176
3.6.14.1.1.2 Desymmetrization Reactions 177
3.6.14.1.1.2.1 Method 1: Desymmetrization of Diynes 177
3.6.14.1.1.2.2 Method 2: Desymmetrization of Diols 179
3.6.14.1.2 Asymmetric Gold(I)-Catalyzed Transformations Proceeding via Initial Allene p-Activation 180
3.6.14.1.2.1 Cycloisomerization Reactions 180
3.6.14.1.2.1.1 Method 1: Hydroindolization 180
3.6.14.1.2.1.2 Method 2: Cycloisomerization of 1,6-Allenenes 181
3.6.14.1.2.1.3 Method 3: Formal [2 + 2]-Cycloaddition Reactions 182
3.6.14.1.2.1.4 Method 4: Formal [4 + 2]-Cycloaddition Reactions 184
3.6.14.1.2.1.5 Method 5: Ring Expansion of Allenylcyclopropanols 186
3.6.14.1.2.2 Addition Reactions 187
3.6.14.1.2.2.1 Method 1: Intramolecular Hydroalkoxylation and Hydroamination 187
3.6.14.1.2.2.2 Method 2: Intramolecular Hydroindolization 196
3.6.14.1.2.2.3 Method 3: Intermolecular Hydroamination 197
3.6.14.1.3 Asymmetric Reactions of Alkenes 198
3.6.14.1.3.1 Method 1: Hydrogenation 198
3.6.14.1.4 Miscellaneous Reactions 199
3.6.14.1.4.1 Method 1: Enantioselective Reactions by Lewis Acidic Heteroatom Coordination 199
3.6.14.1.4.1.1 Variation 1: Aldol Reaction 199
3.6.14.1.4.1.2 Variation 2: Cycloaddition of Münchnones with Electron-Deficient Alkenes 199
3.6.14.1.4.2 Method 2: Enantioselective Reactions of Alkynyl–Gold(I) Species 200
3.6.14.1.4.3 Method 3: Enantioselective Protonation of Silyl Enol Ethers 201
3.6.15 Organometallic Complexes of Gold (Update 2) 206
3.6.15.1 Gold-Catalyzed Reactions of Alkenes 206
3.6.15.1.1 Functionalization of Alkenes 206
3.6.15.1.1.1 Hydrofunctionalization of Unactivated Alkenes 206
3.6.15.1.1.1.1 Method 1: Inter- and Intramolecular Hydroalkylation of Alkenes 206
3.6.15.1.1.1.2 Method 2: Inter- and Intramolecular Hydroarylation of Alkenes 209
3.6.15.1.1.1.2.1 Variation 1: Formation of Hexahydrodibenzo[b,d]furans 211
3.6.15.1.1.1.3 Method 3: Hydroalkoxylation of Alkenes 211
3.6.15.1.1.1.3.1 Variation 1: Formation of Allylic Ethers 213
3.6.15.1.1.1.3.2 Variation 2: Formation of Dihydrobenzofurans from Allyl Aryl Ethers 214
3.6.15.1.1.1.4 Method 4: Inter- and Intramolecular Hydroamination of Alkenes 215
3.6.15.1.1.1.4.1 Variation 1: Formation of Pyrrolidines through Domino Ring Opening/Ring Closing of Methylenecyclopropanes with Sulfonamides 221
3.6.15.1.1.1.4.2 Variation 2: Inter- and Intramolecular Hydroamination of Dienes 222
3.6.15.1.1.1.5 Method 5: Hydrothiolation of Alkenes 224
3.6.15.1.1.2 Michael-Type Addition to a,ß-Unsaturated Carbonyl Compounds 225
3.6.15.1.1.2.1 Method 1: Addition of Indoles and 7-Azaindoles to a,ß-Unsaturated Ketones 226
3.6.15.1.1.2.1.1 Variation 1: Formation of Alkylated Indoles from 2-Alkynylanilines 228
3.6.15.1.1.2.2 Method 2: Addition of Furans and Pyrroles to a,ß-Unsaturated Ketones 229
3.6.15.1.1.2.2.1 Variation 1: Formation of Phenols from Furans and a,ß-Unsaturated Alkynyl Ketones 230
3.6.15.1.1.2.3 Method 3: Addition of Electron-Rich Arenes to a,ß-Unsaturated Carbonyl Compounds and Nitriles 230
3.6.15.1.1.2.4 Method 4: Addition of Carbamates and 4-Toluenesulfonamides to a,ß-Unsaturated Ketones 231
3.6.15.1.1.3 Reactions of Allylic Acetates 232
3.6.15.1.1.3.1 Method 1: Rearrangement of Allylic Acetates 233
3.6.15.1.1.3.2 Method 2: Allyl–Allyl Coupling 235
3.6.15.1.1.3.3 Method 3: Cascade Intermolecular Allylic Substitution/Enyne Cycloisomerization 236
3.6.15.1.1.4 Intermolecular Cyclopropanation of Alkenes 236
3.6.15.1.1.4.1 Method 1: Cyclopropanation via Transfer Reaction from Diazo Compounds 237
3.6.15.1.1.4.2 Method 2: Cyclopropanation via In Situ Generated Gold Carbenes from Propargylic Acetates 240
3.6.15.1.1.4.2.1 Variation 1: Cyclopropanation via Retro-Buchner Reaction 242
3.6.15.1.1.5 Cycloaddition Reactions 243
3.6.15.1.1.5.1 Method 1: Intermolecular [3 + 2] Cycloaddition of Alkynyl Epoxides with Alkenes 244
3.6.15.1.1.5.1.1 Variation 1: Formation of Tricyclic Indoles from Azomethine Ylides 244
3.6.15.1.1.5.2 Method 2: Intermolecular [4 + 2] Cycloaddition of Enynes and Alkynes 245
3.6.15.1.1.5.2.1 Variation 1: Formation of Benzonorcaradienes by Intermolecular [4 + 3] Cycloaddition of Diynes and Alkenes 247
3.6.15.1.1.5.3 Method 3: Intermolecular [3 + 2] and [4 + 3] Cycloadditions of Propargyl Carboxylates and Alkenes or Dienes 248
3.6.15.1.1.5.4 Method 4: 1,3-Dipolar Cycloadditions 252
3.6.15.1.1.5.4.1 Variation 1: Enantioselective 1,3-Dipolar Cycloadditions of Münchnones 253
3.6.15.1.1.6 Oxidation of Alkenes 255
3.6.15.1.1.6.1 Method 1: Formation of Carbonyl Compounds 255
Volume 6: Boron Compounds 262
6.1 Product Class 1: Boron Compounds 262
6.1.3.8 Diborane(4) Compounds 262
6.1.3.8.1 Applications of Diborane(4) Compounds in Organic Synthesis 262
6.1.3.8.1.1 Method 1: Diboration of Alkenes 262
6.1.3.8.1.1.1 Variation 1: Enantioselective Diboration of Terminal Alkenes 262
6.1.3.8.1.1.2 Variation 2: Metal-Free Diboration 263
6.1.3.8.1.2 Method 2: Enantioselective Diboration of Allenes 264
6.1.3.8.1.3 Method 3: Enantioselective Diboration of (E)-1,3-Dienes 265
6.1.3.8.1.4 Method 4: Advances in Alkyne Hydroboration and Diboration 266
6.1.3.8.1.4.1 Variation 1: N-Heterocyclic Carbene–Copper Catalyzed Dihydroboration of Terminal Alkynes 266
6.1.3.8.1.4.2 Variation 2: Borylative Cyclization of Enynes 267
6.1.3.8.1.4.3 Variation 3: Platinum-Catalyzed Diborylation of Arynes 268
6.1.3.8.1.4.4 Variation 4: Differentially Protected Diboron Reagents 269
6.1.3.8.1.5 Method 5: Allylic Substitution 271
6.1.3.8.1.5.1 Variation 1: Nickel-Catalyzed Borylative Ring Opening of Vinyl Epoxides and Aziridines 271
6.1.3.8.1.5.2 Variation 2: Reaction Using a Copper(I)–Bidentate Phosphine Complex 272
6.1.3.8.1.5.3 Variation 3: Reaction Using a Copper(II)–N-Heterocyclic Carbene Complex 273
6.1.3.8.1.5.4 Variation 4: Desymmetrization of meso-Diols 275
6.1.3.8.1.6 Method 6: Copper-Catalyzed Synthesis of Multisubstituted Allenylboronates 276
6.1.3.8.1.7 Method 7: Nickel-Catalyzed Borylative Ring Opening 277
6.1.3.8.1.7.1 Variation 1: Reaction of Vinylcyclopropanes 277
6.1.3.8.1.7.2 Variation 2: Reaction of Aryl Cyclopropyl Ketones 277
6.1.3.8.1.8 Method 8: Copper-Catalyzed Conjugate Addition of 2,2'-Bi-1,3,2-dioxaborolane to a,ß-Unsaturated Carbonyl Compounds 279
6.1.3.8.1.8.1 Variation 1: Racemic Addition to Carbonyl Compounds 279
6.1.3.8.1.8.2 Variation 2: Enantioselective Addition to Carbonyl Compounds 280
6.1.3.8.1.8.3 Variation 3: Addition to Aldehydes and Imines 281
6.1.3.8.1.8.4 Variation 4: Metal-Free Addition to Carbonyl Compounds 283
6.1.3.8.1.8.5 Variation 5: Tertiary Boronic Esters by Addition to 3,3-Disubstituted Enones 284
6.1.3.8.1.8.6 Variation 6: Enantioselective Addition to 3-Boryl Enoates 285
6.1.3.8.1.9 Method 9: Synthesis of Cycloalkylboronates 288
6.1.3.8.1.9.1 Variation 1: Stereospecific Synthesis of Cyclobutylboronates 288
6.1.3.8.1.9.2 Variation 2: Enantioselective Synthesis of Cyclopropylboronates 288
6.1.35.20 Allylboranes 292
6.1.35.20.1 Synthesis of Allylboranes 292
6.1.35.20.1.1 Method 1: Synthesis by Transmetalation 292
6.1.35.20.1.2 Method 2: Synthesis by Hydroboration of 1,3-Dienes or Allenes 300
6.1.35.20.1.2.1 Variation 1: Catalyzed Hydroboration of 1,3-Dienes 300
6.1.35.20.1.2.2 Variation 2: Thermal Hydroboration 302
6.1.35.20.1.3 Method 3: Synthesis by Diboration or Silaboration of 1,3-Dienes, Allenes, or Vinylcyclopropanes 307
6.1.35.20.1.3.1 Variation 1: Diboration of 1,3-Dienes, Enones, or Allenes 307
6.1.35.20.1.3.2 Variation 2: Diboration of Vinylcyclopropanes, Vinyloxiranes, or Aziridines 315
6.1.35.20.1.3.3 Variation 3: Silaboration of 1,3-Dienes or Allenes 317
6.1.35.20.1.4 Method 4: Synthesis by [4 + 2] Cycloaddition 319
6.1.35.20.1.5 Method 5: Synthesis from Diborane(4) Derivatives and Allylic Alcohols, Acetates, or Carbonates 322
6.1.35.20.1.6 Method 6: Synthesis by 3,3-Sigmatropic Rearrangement 328
6.1.35.20.1.7 Method 7: Homologation of Alkenylboron Compounds 331
6.1.35.20.1.8 Method 8: Synthesis by Vinylation of (a-Haloalkyl)boron Derivatives 335
6.1.35.20.1.9 Method 9: Synthesis by Metathesis 338
6.1.35.20.1.10 Method 10: Synthesis by Miscellaneous Methods 342
6.1.35.20.2 Applications of Allylboranes in Organic Synthesis 351
6.1.35.20.2.1 Method 1: Synthesis of Homoallylic Alcohols, Amines, and Hydrazines via Allylboration of C==O and C==N Bonds 352
6.1.35.20.2.1.1 Variation 1: Allylboration of Aldehydes and Ketones 352
6.1.35.20.2.1.2 Variation 2: Allylboration of C==N Bonds 355
6.1.35.20.2.2 Method 2: Allylboration of N==N and C==N Bonds 359
6.1.35.20.2.3 Method 3: Allylation by Cross-Coupling Reactions 360
6.1.35.20.2.4 Method 4: Allylboron–Acetylene Condensation 364
6.1.35.20.2.5 Method 5: Reductive trans-Diallylation of Aromatic N-Heterocycles 367
6.1.35.20.2.6 Method 6: Miscellaneous Methods 369
Volume 16: Six-Membered Hetarenes with Two Identical Heteroatoms 378
16.15 Product Class 15: Quinoxalines 378
16.15.5 Quinoxalines 378
16.15.5.1 Synthesis by Ring-Closure Reactions 380
16.15.5.1.1 By Annulation to an Arene 380
16.15.5.1.1.1 By Formation of Two N--C Bonds and One C--C Bond 380
16.15.5.1.1.1.1 Fragments N--Arene--N, C, and C 380
16.15.5.1.1.1.1.1 Method 1: From Benzene-1,2-diamine, Aldehydes, and Isocyanides 380
16.15.5.1.1.1.1.2 Method 2: From Benzene-1,2-diamine, Aldehydes, and Tosylmethyl Isocyanide 381
16.15.5.1.1.2 By Formation of Two N--C Bonds 382
16.15.5.1.1.2.1 Fragments N--Arene--N and C--C 382
16.15.5.1.1.2.1.1 Method 1: From Benzene-1,2-diamines and Glyoxal or Its Synthetic Equivalents 383
16.15.5.1.1.2.1.1.1 Variation 1: From Substituted Benzene-1,2-diamines and 1,4-Dioxane-2,3-diol 383
16.15.5.1.1.2.1.1.2 Variation 2: From Benzene-1,2-diamine and Hexahydro-[1,4]dioxino[2,3-b]-1,4-dioxin-2,3,6,7-tetraol 383
16.15.5.1.1.2.1.1.3 Variation 3: From Benzene-1,2-diamine and Disodium 1,2-Dihydroxyethane-1,2-disulfonate 384
16.15.5.1.1.2.1.1.4 Variation 4: From Benzene-1,2-diamine and N,N'-Dicyclohexylethane-1,2-diimine 385
16.15.5.1.1.2.1.2 Method 2: From Benzene-1,2-diamines and a-Oxoaldehydes or Their Synthetic Equivalents 385
16.15.5.1.1.2.1.2.1 Variation 1: From Benzene-1,2-diamine and a,a-Dihydroxy Ketones 386
16.15.5.1.1.2.1.2.2 Variation 2: From Benzene-1,2-diamine and a-Ketoaldehyde Oximes or Hydrazones 386
16.15.5.1.1.2.1.3 Method 3: From Benzene-1,2-diamines and 1,2-Diketones or Their Synthetic Equivalents 387
16.15.5.1.1.2.1.3.1 Variation 1: Synthesis of Quinoxalinium Salts from N-Substituted Benzene-1,2-diamines and Butane-2,3-dione 388
16.15.5.1.1.2.1.3.2 Variation 2: From Benzene-1,2-diamines and Alkynes under Oxidative Conditions 389
16.15.5.1.1.2.1.3.3 Variation 3: From Benzene-1,2-diamines and Diiminosuccinonitrile 389
16.15.5.1.1.1.1.4 Method 4: From Benzene-1,2-diamines and a-Oxo Acids or Their Derivatives (The Hinsberg Reaction) 390
16.15.5.1.1.1.1.5 Method 5: From Benzene-1,2-diamines and Oxalic Acid Derivatives 391
16.15.5.1.1.1.1.5.1 Variation 1: From Benzene-1,2-diamines and Alkyl Alkoxy(imino)acetates 392
16.15.5.1.1.2.1.6 Method 6: From Benzene-1,2-diamines and Dialkyl Acetylenedicarboxylates 393
16.15.5.1.1.2.1.7 Method 7: From Benzene-1,2-diamine and Aryl Methyl Ketones and Their Derivatives 394
16.15.5.1.1.2.1.7.1 Variation 1: Oxidative Cyclization of Benzene-1,2-diamine and Acetylpyridines 394
16.15.5.1.1.2.1.7.2 Variation 2: From Benzene-1,2-diamines and Hydroxymethyl Ketones 395
16.15.5.1.1.2.1.7.3 Variation 3: From Benzene-1,2-diamines and Halomethyl Ketones 396
16.15.5.1.1.2.1.7.4 Variation 4: From Benzene-1,2-diamines and Aminomethyl Ketones 397
16.15.5.1.1.2.1.8 Method 8: From Benzene-1,2-diamines and a-Diazo Ketones 397
16.15.5.1.1.2.2 Fragments N--C--C--N and C--C (Arene) 398
16.15.5.1.1.2.2.1 Method 1: From 1,2-Diamines and Benzo-1,4-quinones and -1,2-quinones 398
16.15.5.1.1.2.3 Fragments N--Arene and N--C--C 398
16.15.5.1.1.2.3.1 Method 1: Synthesis of Quinoxalinone N-Oxides from Anilines and 1,1,2-Trichloro-2-nitroethene 398
16.15.5.1.1.3 By Formation of One N--C and One C--C Bond 399
16.15.5.1.1.4 By Formation of One N--C Bond 400
16.15.5.1.1.4.1 Fragment N--Arene--N--C--C 400
16.15.5.1.1.4.1.1 Method 1: Intramolecular Reactions of C-Electrophiles with a 2-Aminophenyl Group 400
16.15.5.1.1.4.1.1.1 Variation 1: Intramolecular Reductive Cyclization of N-(2-Nitrophenyl)-2-oxopropanamide 400
16.15.5.1.1.4.1.1.2 Variation 2: From N-(2-Nitrophenyl)glycines by a Reductive Cyclization/Oxidation Sequence 400
16.15.5.1.1.4.1.1.3 Variation 3: Intramolecular Reductive Cyclization of 2-(2-Nitrophenylamino)-2-oxoacetates 401
16.15.5.1.1.4.1.2 Method 2: Quinoxalinone N-Oxides by Intramolecular C-Nucleophilic Attack on a 2-Nitrophenyl Group 402
16.15.5.1.1.4.2 Fragment Arene--N--C--C--N 403
16.15.5.1.1.4.2.1 Method 1: Intramolecular Cyclization of (Phenylimino)acetaldehyde 403
16.15.5.1.1.4.2.2 Method 2: Unsymmetrical 2,3-Substituted Quinoxalines from N-Aryl Nitroketene N,S-Acetals and Phosphoryl Chloride 403
16.15.5.1.2 By Annulation to the Heterocyclic Ring 404
16.15.5.1.2.1 By Formation of Two C--C Bonds 404
16.15.5.1.2.1.1 Fragments C--Hetarene--C and C--C 404
16.15.5.1.2.1.1.1 Method 1: Cycloaddition of 2,3-Bis(dibromomethyl)pyrazine to Dienophiles 404
16.15.5.2 Synthesis by Ring Transformation 404
16.15.5.2.1 By Ring Enlargement 404
16.15.5.2.1.1 Method 1: From Benzimidazoles and 1,2-Diketones 404
16.15.5.2.1.2 Method 2: Quinoxalines from Benzofurazans and 2-Aminoethanol 405
16.15.5.2.1.3 Method 3: Quinoxaline 1,4-Dioxides from Benzofurazan 1-Oxides and Enolizable Carbonyl Compounds 405
16.15.5.2.1.4 Method 4: From Benzene-1,2-diamines and 1H-Indole-2,3-diones (Isatins) 406
16.15.5.3 Synthesis by Ring Modification 407
16.15.5.3.1 Oxidative Ring Modifications 407
16.15.5.3.1.1 Method 1: Aromatization by Oxidation of 1,2,3,4-Tetrahydroquinoxalines 407
16.15.5.3.1.2 Method 2: Aromatization by Oxidation of 1,2-Dihydroquinoxaline Derivatives 408
16.15.5.3.1.3 Method 3: Quinoxaline N-Oxides by N-Oxidation of Quinoxalines 409
16.15.5.3.1.4 Method 4: Quinoxaline 1,4-Dioxides by N-Oxidation of Quinoxalines 410
16.15.5.3.1.4.1 Variation 1: Quinoxaline 1,4-Dioxides by N-Oxidation of Quinoxaline N-Oxides 411
16.15.5.3.1.5 Method 5: Quinoxaline-2,3-diones from Quinoxalin-2-ones by Oxidation 412
16.15.5.3.2 Reductive Ring Modifications 412
16.15.5.3.2.1 Method 1: Reduction of Quinoxalines to 1,2,3,4-Tetrahydroquinoxalines 412
16.15.5.3.2.2 Method 2: Reduction of Quinoxalin-2-ones to 3,4-Dihydroquinoxalin-2(1H)-ones 414
16.15.5.3.2.3 Method 3: Reduction of Quinoxaline N-Oxides to Quinoxalines 414
16.15.5.3.2.4 Method 4: Reduction of Quinoxaline 1,4-Dioxides to Quinoxalines 415
16.15.5.3.3 Addition of C-Nucleophiles 416
16.15.5.3.3.1 Method 1: Addition of Ketone Enols to Quinoxalin-2-ones 416
16.15.5.3.3.2 Method 2: Addition of Anions Derived from 1-Haloalkyl Sulfones 416
16.15.5.3.3.3 Method 3: Addition of Organometallics 417
16.15.5.3.3.4 Method 4: Addition of Potassium Phenylacetylide to Quinoxaline 1-Oxides 418
16.15.5.3.3.5 Method 5: Cycloaddition Reactions 418
16.15.5.3.4 Elimination Reactions 419
16.15.5.3.4.1 Method 1: Aromatization by Elimination from 1-Acyl-1,2-dihydroquinoxalines 419
16.15.5.4 Ring Functionalization by Substitution of Ring Hydrogens or N-Alkylation 419
16.15.5.4.1 Method 1: Hydrogen–Deuterium Exchange 419
16.15.5.4.2 Method 2: Alkylation 420
16.15.5.4.2.1 Variation 1: Radical C-Alkylation 420
16.15.5.4.2.2 Variation 2: C-Alkylation of Quinoxaline Anions 420
16.15.5.4.2.3 Variation 3: N-Alkylation of Quinoxalin-2-ones 421
16.15.5.4.2.4 Variation 4: Synthesis of Onium Salts 422
16.15.5.4.3 Method 3: Acylation 423
16.15.5.4.3.1 Variation 1: Free-Radical Acylation of Quinoxaline 423
16.15.5.4.3.2 Variation 2: Electrophilic Acylation of Quinoxaline Anions 424
16.15.5.4.4 Method 4: Cyanation 424
16.15.5.4.5 Method 5: Halogenation 425
16.15.5.4.6 Method 6: Chlorosulfonylation 426
16.15.5.4.7 Method 7: Nitration 426
16.15.5.4.8 Method 8: Amination 427
16.15.5.5 Synthesis by Substituent Transformation 427
16.15.5.5.1 Transformation of Carbon Functionalities 427
16.15.5.5.1.1 Method 1: Substitution with Hydrogen 427
16.15.5.5.1.2 Method 2: Rearrangements of Carbon Functionalities 428
16.15.5.5.1.2.1 Variation 1: Curtius Rearrangement 428
16.15.5.5.1.2.2 Variation 2: Hofmann Rearrangement 428
16.15.5.5.1.3 Method 3: Oxidation 429
16.15.5.5.1.4 Method 4: Halogenation 430
16.15.5.5.1.5 Method 5: Reductive Amination of Quinoxaline-2-carbaldehyde 431
16.15.5.5.1.6 Method 6: Amidation of Quinoxaline Carboxylic Acids and Their Derivatives 431
16.15.5.5.1.7 Method 7: Reactions with Electrophiles 432
16.15.5.5.1.7.1 Variation 1: 3-Substitution of 3-Methylquinoxalin-2(1H)-one 432
16.15.5.5.1.7.2 Variation 2: Knoevenagel Reaction 433
16.15.5.5.2 Transformation of Halogen Functionalities 434
16.15.5.5.2.1 Method 1: Dehalogenation 434
16.15.5.5.2.2 Method 2: Halogen Exchange 435
16.15.5.5.2.3 Method 3: Halogen–Metal Exchange 435
16.15.5.5.2.4 Method 4: Reaction with C-Nucleophiles 436
16.15.5.5.2.4.1 Variation 1: Cyanation 436
16.15.5.5.2.4.2 Variation 2: a-Hetarylation of Esters, Lactones, Amides, and Nitriles with 2-Chloroquinoxaline 436
16.15.5.5.2.4.3 Variation 3: Cross Coupling with Organolithiums 437
16.15.5.5.2.4.4 Variation 4: Cross Coupling with Grignard Reagents 438
16.15.5.5.2.4.5 Variation 5: Cross Coupling with Organozinc Compounds 438
16.15.5.5.2.4.6 Variation 6: Stille Cross Coupling 439
16.15.5.5.2.4.7 Variation 7: Cross Coupling with Organoboron Compounds 439
16.15.5.5.2.4.8 Variation 8: Heck Cross Coupling 440
16.15.5.5.2.4.9 Variation 9: Sonogashira Cross Coupling 441
16.15.5.5.2.5 Method 5: Reaction with N-Nucleophiles 442
16.15.5.5.2.6 Method 6: Reaction with O-Nucleophiles 443
16.15.5.5.2.7 Method 7: Reaction with S-Nucleophiles 443
16.15.5.5.3 Transformation of Nitrogen Functionalities 444
16.15.5.5.3.1 Method 1: Reduction of Nitro Groups 444
16.15.5.5.3.2 Method 2: Substitution with a Halogen via Diazotization 444
16.15.5.5.3.3 Method 3: N-Alkylation 444
16.15.5.5.3.4 Method 4: N-Acylation 444
16.15.5.5.4 Transformation of Oxygen Functionalities 445
16.15.5.5.4.1 Method 1: Haloquinoxalines from the Corresponding Oxo Derivatives 445
16.15.5.5.4.2 Method 2: Reaction with C-Nucleophiles 446
16.15.5.5.4.3 Method 3: Reactions with N-Nucleophiles 447
16.15.5.5.4.4 Method 4: Reaction with S-Nucleophiles 447
16.15.5.5.4.5 Method 5: O-Alkylation 447
16.15.5.5.4.6 Method 6: O-Demethylation 448
16.15.5.5.5 Transformation of Sulfur Functionalities 448
16.15.5.5.5.1 Method 1: Oxidation 448
16.15.5.5.5.2 Method 2: Reaction with C-Nucleophiles 449
16.15.5.5.5.3 Method 3: Reaction with N-Nucleophiles 450
16.15.5.5.5.4 Method 4: S-Alkylation 450
16.15.5.5.5.5 Method 5: C--S Bond Cleavage 451
Volume 21: Three Carbon--Heteroatom Bonds: Amides and Derivatives Peptides
21.16 Synthesis of Scalemic Amides by Kinetic Resolution 462
21.16.1 Method 1: Kinetic Resolution by Acylation with Stoichiometric Amounts of Chiral Acylating Reagents 462
21.16.2 Method 2: Kinetic Resolution with Catalytic Amounts of a Chiral Promoter 467
21.16.2.1 Variation 1: Kinetic Resolution of Amines with Attenuated Reactivities 467
21.16.2.2 Variation 2: Kinetic Resolution with Azlactone-Derived Acylating Reagents 469
21.16.2.3 Variation 3: Kinetic Resolution with Carboxylic Acid Anhydrides as Acylating Reagents 471
21.16.2.4 Variation 4: Kinetic Resolution with a'-Hydroxyenones as Acylating Reagents 473
21.16.2.5 Variation 5: Kinetic Resolution with Carboxylic Acids as Acylating Reagents 476
Volume 27: Heteroatom Analogues of Aldehydes and Ketones 480
27.16 Product Class 16: Azines 480
27.16.3 Azines 480
27.16.3.1 Synthesis of Azines 480
27.16.3.1.1 1,4-Disubstituted Azines 480
27.16.3.1.1.1 Method 1: Reaction of Aldehydes with Hydrazine 480
27.16.3.1.1.2 Method 2: Reaction of Aldehyde Hydrazones with Aldehydes 481
27.16.3.1.1.3 Method 3: Hydrazone Oxidation 482
27.16.3.1.1.4 Method 4: Reaction of Aldehyde Hydrazones with Disulfur Compounds 483
27.16.3.1.1.5 Method 5: Reaction of Semicarbazones with Aldehydes 483
27.16.3.1.2 Trisubstituted Azines 484
27.16.3.1.2.1 Method 1: Reaction of Aldehyde Hydrazones with Ketones 484
27.16.3.1.2.2 Method 2: Reaction of Ketone Hydrazones with Aldehydes 484
27.16.3.1.3 Tetrasubstituted Azines 485
27.16.3.1.3.1 Method 1: Ketone Dimerization with Hydrazine 485
27.16.3.1.3.2 Method 2: Reaction of Hydrazones with Ketones 486
27.16.3.1.3.3 Method 3: Diazoalkane Dimerization 487
27.16.3.1.3.4 Method 4: Imine Oxidation 487
27.16.3.2 Applications of Azines in Organic Synthesis 488
27.16.3.2.1 Method 1: Oxidation and Reduction 488
27.16.3.2.2 Method 2: Addition Reactions 490
27.16.3.2.3 Method 3: Formation of Organometallic Complexes 491
27.16.3.2.4 Method 4: Intramolecular Cyclization Reactions 492
27.16.3.2.5 Method 5: Cycloaddition Reactions 493
27.16.3.2.6 Method 6: Hydrolytic Cleavage 494
27.16.3.2.7 Method 7: Ugi Reaction 495
27.17 Product Class 17: Hydrazones 500
27.17.5 Hydrazones 500
27.17.5.1 N-Unsubstituted Hydrazones 500
27.17.5.1.1 Synthesis of N-Unsubstituted Hydrazones 500
27.17.5.1.1.1 Method 1: Synthesis from Aldehydes and Ketones 500
27.17.5.1.1.1.1 Variation 1: From Oximes 500
27.17.5.1.1.2 Method 2: Synthesis from Diazo Compounds 501
27.17.5.1.1.3 Method 3: Synthesis from Unsaturated Hydrocarbons 503
27.17.5.1.1.3.1 Variation 1: From Terminal Alkynes 503
27.17.5.1.1.3.2 Variation 2: From Allenes 504
27.17.5.1.1.3.3 Variation 3: From Fluoroalkenes 504
27.17.5.1.2 Applications of N-Unsubstituted Hydrazones in Organic Synthesis 505
27.17.5.1.2.1 Method 1: Reductive Elimination of the Hydrazono Group 505
27.17.5.1.2.2 Method 2: Synthesis of Nitrogen Heterocycles 506
27.17.5.1.2.3 Method 3: Synthesis of Diazo Compounds by Oxidation 507
27.17.5.1.2.4 Method 4: Synthesis of Halogenated Alkenes 509
27.17.5.2 N-Monosubstituted Hydrazones 511
27.17.5.2.1 Synthesis of N-Monosubstituted Hydrazones 511
27.17.5.2.1.1 Method 1: Synthesis from Aldehydes and Ketones 511
27.17.5.2.1.1.1 Variation 1: Hydroformylation–Hydrazone Formation from Alkenes 512
27.17.5.2.1.1.2 Variation 2: Synthesis from Masked Carbonyl Groups 513
27.17.5.2.1.2 Method 2: Synthesis by Arylation of Benzophenone Hydrazone 513
27.17.5.2.1.3 Method 3: Synthesis from Activated Methylene Compounds 514
27.17.5.2.1.3.1 Variation 1: Reaction with Benzotriazoles 514
27.17.5.2.1.3.2 Variation 2: Reaction with Diazonium Salts 514
27.17.5.2.1.4 Method 4: Synthesis from Terminal Alkynes 515
27.17.5.2.1.5 Method 5: Synthesis from Diazo Esters 516
27.17.5.2.2 Applications of N-Monosubstituted Hydrazones in Organic Synthesis 516
27.17.5.2.2.1 Method 1: Synthesis of Nitrogen Heterocycles 517
27.17.5.2.2.1.1 Variation 1: Fischer Indole Synthesis from N-Arylhydrazones 517
27.17.5.2.2.2 Method 2: N-tert-Butylhydrazones as Acyl Anion Equivalents 517
27.17.5.2.2.3 Method 3: Synthesis of N,N-Disubstituted Hydrazones by Acylation 518
27.17.5.2.2.4 Method 4: Synthesis of Bicyclic Diazenium Salts 518
27.17.5.3 N,N-Disubstituted Hydrazones 519
27.17.5.3.1 Synthesis of N,N-Disubstituted Hydrazones 519
27.17.5.3.1.1 Method 1: Synthesis from Aldehydes and Ketones 519
27.17.5.3.1.1.1 Variation 1: Synthesis from Masked Aldehydes and Ketones 520
27.17.5.3.1.1.2 Variation 2: Solid-Supported Synthesis 520
27.17.5.3.1.2 Method 2: Synthesis from Unsaturated Hydrocarbons 522
27.17.5.3.1.3 Method 3: Synthesis from N-Monosubstituted Hydrazones 523
27.17.5.3.2 Applications of N,N-Disubstituted Hydrazones in Organic Synthesis 523
27.17.5.3.2.1 Method 1: Alkylation of Hydrazone Anions 523
27.17.5.3.2.1.1 Variation 1: Solid-Supported Synthesis 524
27.17.5.3.2.1.2 Variation 2: Alkylation of Cyclic Carbamates Derived from N-Acyl-N-alkylhydrazones 526
27.17.5.3.2.2 Method 2: Primary Amine Synthesis 527
27.17.5.3.2.2.1 Variation 1: Solid-Supported Synthesis 528
27.17.5.3.2.3 Method 3: Radical Reactions 529
27.17.5.3.2.3.1 Variation 1: Radical Cyclization 529
27.17.5.3.2.3.2 Variation 2: Radical Addition 530
27.17.5.3.2.4 Method 4: Cycloaddition Reactions 531
27.17.5.3.2.4.1 Variation 1: [4 + 2]-Cycloaddition Reactions 531
27.17.5.3.2.4.2 Variation 2: [2 + 2]-Cycloaddition Reactions 531
27.17.5.3.2.5 Method 5: Cleavage of N,N-Dialkylhydrazones 532
27.17.5.3.2.5.1 Variation 1: Solid-Phase Synthesis of Nitriles 533
27.17.5.4 N-Sulfonylated Hydrazones 533
27.17.5.4.1 Synthesis of N-Sulfonylated Hydrazones 533
27.17.5.4.1.1 Method 1: Synthesis from Aldehydes and Ketones 533
27.17.5.4.1.1.1 Variation 1: Synthesis from O,O-Acetals 535
27.17.5.4.1.2 Method 2: Synthesis from Nitriles 535
27.17.5.4.1.3 Method 3: N-Alkylation of N-Tosylhydrazones 536
27.17.5.4.2 Applications of N-Sulfonylated Hydrazones in Organic Synthesis 537
27.17.5.4.2.1 Method 1: Synthesis of Unsaturated Hydrocarbons 537
27.17.5.4.2.1.1 Variation 1: Synthesis of Alkenes 537
27.17.5.4.2.1.2 Variation 2: Synthesis of Allenes 541
27.17.5.4.2.1.3 Variation 3: Synthesis of Alkynes 542
27.17.5.4.2.2 Method 2: N-Sulfonylated Hydrazones in Reduction Reactions 543
27.17.5.4.2.2.1 Variation 1: Synthesis of Sulfides and Ethers 544
27.17.5.4.2.2.2 Variation 2: Synthesis of Sulfones 545
27.17.5.4.2.2.3 Variation 3: Synthesis of Arenes from Arylboronic Acids 546
27.17.5.4.2.3 Method 3: Synthesis of a-Alkylated and a,a-Dialkylated N-Tosylhydrazones 547
27.17.5.4.2.4 Method 4: Synthesis of Nitrogen Heterocycles 548
27.18 Product Class 18: Hydrazonium Compounds 556
27.18.3 Hydrazonium Compounds 556
27.18.3.1 1,1,1-Trialkyl-2-alkylidenehydrazinium Compounds 556
27.18.3.1.1 Synthesis of 1,1,1-Trialkyl-2-alkylidenehydrazinium Compounds 556
27.18.3.1.1.1 Method 1: Alkylation of Hydrazone Compounds 556
27.18.3.1.2 Applications of 1,1,1-Trialkyl-2-alkylidenehydrazinium Compounds in Organic Synthesis 557
27.18.3.1.2.1 Method 1: Synthesis of Azirines 557
27.18.3.1.2.2 Method 2: Synthesis of Pyrroles 558
27.18.3.1.2.3 Method 3: Synthesis of Ketones 558
Author Index 560
Abbreviations 590
List of All Volumes 596

Textauszug

1.4.5 Organometallic Complexes of Cobalt (Update 2012)

M. Amatore, C. Aubert, M. Malacria, and M. Petit

General Introduction

The present chapter is an update of the first report on organometallic cobalt complexes in Science of Synthesis (see Section 1.4). It summarizes the more recent and most relevant advances concerning the use and the synthesis of important cobalt complexes. During the decade 2000–2010, two major developments were made concerning cobalt complexes:

The first involves the extensive use of cobalt–η5-dienyl complexes not only in the context of the synthesis of new complexes, but also in terms of powerful applications in a wide range of reactions. This can be related to the increase in the number of reviews in this area since the beginning of the new millennium.[1–9]

The second major development in the organometallic chemistry of cobalt complexes is the use of more-convenient and easy-to-handle complexes based on cobalt(II) or -(III) salts. From economic and environmental points of view, these complexes represent an interesting alternative to the well-known cyclopentadienylcobalt(I) [Co(Cp)L2] or octacarbonyldicobalt(0) [Co2(CO)8] catalysts. Although early applications of these complexes in organic synthesis have been reported, their use has been generalized only recently. Because of their low cost, low toxicity, and relatively high stability, these cobalt complexes have gained an increasingly important role in the field of cross-coupling reactions, cycloadditions, alkene functionalizations, C—H bond activations, and even the chemistry of strained rings.[5,10] The most commonly employed catalytic systems are combinations of cobalt(II) or -(III) salts with defined ligands, such as phosphines or amines, that can be prepared in a previous step or generated in situ under reductive conditions. Another class of complexes that have shown high efficiency is represented by cobalt(II) or -(III) complexes incorporating macrocyclic ligands such as porphyrins, salens, or cobaloximes. Finally, cobalt(I) species obtained from tetrakis(trimethylphosphine)cobalt(0) have been employed with success in the course of C—H bond activation processes for the generation of new cobalt complexes. This review provides an overview of contemporary methods that require the preparation and the use of these complexes.

1.4.5.1 Cobalt–η5-Dienyl Complexes

1.4.5.1.1 Synthesis of Cobalt–η5-Dienyl Complexes

1.4.5.1.1.1 Method 1: Synthesis of Chiral Dicarbonyl(η5-cyclopentadienyl)cobalt(I) and (η5-Cyclopentadienyl)(η4-diene)cobalt(I) Complexes

In the course of asymmetric reactions, cobalt-mediated [2 + 2 + 2] cycloaddition has been for a long time one of the most difficult challenges. Chiral cobalt–η5-dienyl complexes may be obtained by introducing an asymmetric cyclopentadienyl moiety as a permanent ligand. Two general procedures are reported; these differ in the nature of the labile ligand on the complex.[11,12]

1.4.5.1.1.1.1 Variation 1: Synthesis of Chiral Dicarbonyl(η5-cyclopentadienyl)cobalt(I) Complexes by Oxidative Addition

The reaction between octacarbonyldicobalt(0), a readily available starting material, and the freshly distilled chiral cyclopentadiene 1 in a refluxing chlorinated solvent in the absence of light gives the desired chiral cobalt(I) complex 2 in moderate to good yields (▶ Scheme 1).[11]

▶ Scheme 1 Synthesis of a Dicarbonyl(η5-cyclopentadienyl)cobalt(I) Complex from Octacarbonyldicobalt(0) and a Chiral Cyclopentadiene[11]

Dicarbonyl{η5-(3S,4S)-3,4-(isopropylidenedioxy)bicyclo[4.3.0]nona-6,8-dienyl}cobalt(I) (2); Typical Procedure:[11]

A soln of chiral cyclopentadiene 1 (0.58 g, 3.0 mmol) in CH2Cl2 (10 mL) and pent-1-ene (5 mL) was degassed by three freeze–pump–thaw cycles, added to Co2(CO)8 (0.85 g, 2.5 mmol) in a round-bottomed flask equipped with a reflux condenser, and the mixture was heated at reflux in the dark under N2 for 30 h. The solvent was removed under reduced pressure, and the oil was taken up in degassed pentane. The mixture was purified by chromatography [alumina (activity 3), degassed Et2O/pentane 1:4] under N2. A single red fraction was obtained, which crystallized upon removal of the solvent under reduced pressure to provide a red solid; yield: 0.39 g (43%); mp 72–73 °C; [α]D26 +70 (c 0.00095, 95% EtOH).

1.4.5.1.1.1.2 Variation 2: Synthesis of Chiral (η5-Cyclopentadienyl)(η4-diene)cobalt(I) Complexes by Substitution of Ligands

Several chiral (η5-cyclopentadienyl)cobalt(I)–ligand complexes (ligand = cyclooctadiene, e.g. 3 and 4, or norbornadiene) are prepared by substitution reactions of tris(triphenylphosphine)cobalt(I) chloride using chiral lithium cyclopentadienides and cyclooctadiene or norbornadiene (▶ Scheme 2).[12,13]

▶ Scheme 2 Synthesis of Chiral (η5-Cyclopentadienyl)(η4-diene)cobalt(I) Complexes[12,13]

(+)-(η4-Cycloocta-1,5-diene)(η5-1-neomenthylindenyl)cobalt(I) (3); Typical Procedure:[12]

A 2.5 M soln of BuLi in hexanes (2 mL, 5 mmol) was added in one portion to a soln of (–)-3-neomenthylindene (1.27 g, 5 mmol) in THF (15 mL) at –78 °C. The mixture was stirred for 5 min, the temperature was allowed to rise to 20 °C for 30 min, and stirring was continued for 2 h at rt. The soln of (1-neomenthylindenyl)lithium was again cooled to –78 °C, and CoCl(PPh3)3 (4.41 g, 5 mmol) was added. The stirred soln was allowed to warm to rt over 1 h and then stirred for an additional 1 h. Cycloocta-1,5-diene (0.92 mL, 7.5 mmol) was added to the dark red mixture, which was then heated to reflux for 0.5 h. The color soon changed to red-orange, and the soln was cooled and filtered through a thin pad of degassed silica gel (2 × 3 cm), eluting with THF. The solvent was removed under reduced pressure, and the oily residue was dried for 1 h under high vacuum and purified by column chromatography [degassed silica gel (1.5 × 30 cm)]. Elution with pentane allowed the separation of the main diastereomer as the first red-orange fraction, and the more slowly moving second minor fraction was set aside. The eluate was concentrated under reduced pressure to a volume of 5 mL. Cooling to –78 °C caused the precipitation of the complex 3 as a dark red crystalline compound, which was collected by filtration and dried under high vacuum; yield: 1.11 g (53%); mp 89 °C; [α]D20 +156 (c 0.06, toluene).

(η4-Cycloocta-1,5-diene){η5-(3S,4S)-3,4-(isopropylidenedioxy)bicyclo[4.3.0]nona-6,8-dienyl}cobalt(I) (4); Typical Procedure:[13]

A soln of cyclopentadiene 1 (1.44 g, 7.5 mmol) in THF (20 mL) was treated with a 10% suspension of LDA (0.8 g, 7.5 mmol) in hexanes. The mixture was stirred for 5 min, and a suspension of CoCl(PPh3)3 (6.35 g, 7.2 mmol) and cycloocta-1,5-diene (1.29 mL, 10.5 mmol) in toluene (40 mL) was added. After it had been stirred for 1 h at rt, the dark red mixture was heated to 80 °C for 1 h, resulting finally in a clear orange soln. The mixture was cooled and filtered through a short column of silica gel (1.5 cm × 3 cm) degassed by three argon– vacuum pump cycles, 1 h each. Volatiles were removed under reduced pressure, and the residue was dissolved in pentane (20 mL) and left overnight at 0 °C. Precipitated Ph3P was filtered off, and the soln was filtered through a column of degassed silica gel (1.5 cm × 20 cm), an orange band being eluted with pentane. The soln was concentrated to a volume of 10 mL and cooled to –78 °C to crystallize 4 as orange needles; yield: 1.82 g (68%); mp 102 °C; [α]D20 +5.5 (c 0.17, toluene).

1.4.5.1.1.2 Method 2: Synthesis of (Alkene)carbonyl(η5-cyclopentadienyl)cobalt(I) Complexes via Displacement of One Carbonyl Moiety

Among the commercially available cyclopentadienylcobalt catalysts, dicarbonyl(η5-cyclopentadienyl)cobalt(I) is probably the most widely used. Its activation usually requires heat and/or visible light. The use of (η4-cycloocta-1,5-diene)(η5-cyclopentadienyl)cobalt(I), which has been employed mostly for the preparation of pyridines, also requires high temperatures and/or light. Conversely, (η5-cyclopentadienyl)bis(ethene)cobalt(I), which is also employed frequently, is active at room temperature or lower temperatures. However, these very efficient catalysts are all very sensitive to air and require the use of distilled and thoroughly degassed solvents. The challenge of finding easy-to-handle air-stable cobalt catalysts has been addressed by the use of complexes of the type (alkene)carbonyl(η5-cyclopentadienyl)cobalt(I), e.g. 5 and 6 (▶ Schemes 3 and 4).[14,15] These complexes do not need degassed solvents but do, however, still need energetic activation to be reactive.

▶ Scheme 3 Synthesis of...

Produkt-Details

• Erscheint lt. Verlag: 14.5.2014
• Verlagsort: Stuttgart
• Sprache: englisch
• Themenwelt: Naturwissenschaften ► Chemie ► Organische Chemie
• Themenwelt: Technik
• Schlagworte: azines • Boron • Chemie • Chemische Synthese • chemistry of organic compound • chemistry organic reaction • chemistry reference work • chemistry synthetic methods • Cobalt • compound functional group • compound organic synthesis • Gold • hydrazones • hydrazonium compounds • Mechanism • Method • methods in organic synthesis • methods peptide synthesis • Organic Chemistry • organic chemistry functional groups • organic chemistry reactions • organic chemistry review • organic chemistry synthesis • ORGANIC CHEM ISTRY SYNTHESIS • organic method • organic reaction • organic reaction mechanism • ORGANI C REACTION MECHANISM • Organic Syntheses • organic synthesis • organic synthesis reference work • Organisch-chemische Synthese • Organische Chemie • Organometallic • Peptide synthesis • Practical • practical organic chemistry • quinoxalines • Reaction • reference work • Review • review organic synthesis • review synthetic methods • REVIEW SYNTHE TIC METHODS • scalemic amides • Synthese • synthesis • Synthetic chemistry • Synthetic Methods • Synthetic Organic Chemistry • synthetic transformation
• ISBN-10: 3-13-178851-8 / 3131788518
• ISBN-13: 978-3-13-178851-1 / 9783131788511