Bode / Amatore / Hall Science of Synthesis Knowledge Updates 2012 Vol. 3

1. Auflage 2014
ISBN: 978-3-13-178841-2
Verlag: Thieme
Format: PDF
Kopierschutz: Adobe DRM (»Systemvoraussetzungen)

E-Book, Englisch, 592 Seiten, PDF, Format (B × H): 170 mm x 240 mm

Reihe: Science of Synthesis

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.

Zielgruppe

Wissenschaftler

Autoren/Hrsg.

Amatore, Muriel

Aubert, Corinne

Campbell, Matthew

Ferris, Grace

Dav,

Bode, Jeffrey W.

Hall, Dennis

Krause, Norbert

Li, Jie Jack

Plietker, Bernd

Schaumann, Ernst

Fachgebiete

• Naturwissenschaften Chemie Organische Chemie

Inhaltsverzeichnis

1;Science of Synthesis: Knowledge Updates 2012/3;1
1.1;Title page;5
1.2;Imprint;7
1.3;Preface;8
1.4;Abstracts;10
1.5;Overview;18
1.6;Table of Contents;20
1.7;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
1.7.1;1.4 Product Class 4: Organometallic Complexes of Cobalt;36
1.7.1.1;1.4.5 Organometallic Complexes of Cobalt;36
1.7.1.1.1;1.4.5.1 Cobalt–.5-Dienyl Complexes;36
1.7.1.1.1.1;1.4.5.1.1 Synthesis of Cobalt–.5-Dienyl Complexes;36
1.7.1.1.1.1.1;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
1.7.1.1.1.1.1.1;1.4.5.1.1.1.1 Variation 1: Synthesis of Chiral Dicarbonyl(.5-cyclopentadienyl)cobalt(I) Complexes by Oxidative Addition;37
1.7.1.1.1.1.1.2;1.4.5.1.1.1.2 Variation 2: Synthesis of Chiral (.5-Cyclopentadienyl)(.4-diene)cobalt(I) Complexes by Substitution of Ligands;37
1.7.1.1.1.1.2;1.4.5.1.1.2 Method 2: Synthesis of (Alkene)carbonyl(.5-cyclopentadienyl)cobalt(I) Complexes via Displacement of One Carbonyl Moiety;39
1.7.1.1.1.1.3;1.4.5.1.1.3 Method 3: Synthesis of (.5-Cyclopentadienyl)(.4-diene)cobalt(I) Complexes via Substitution of Ligands;40
1.7.1.1.1.1.4;1.4.5.1.1.4 Method 4: Synthesis of (.5-Cyclopentadienyl)cobalt–N-Heterocyclic Carbene Complexes by Exchange of Ligands;40
1.7.1.1.1.1.4.1;1.4.5.1.1.4.1 Variation 1: Synthesis of Carbonyl(.5-cyclopentadienyl)cobalt–N-Heterocyclic Carbene Complexes;41
1.7.1.1.1.1.4.2;1.4.5.1.1.4.2 Variation 2: Synthesis of (.5-Cyclopentadienyl)(ethene)cobalt–N-Heterocyclic Carbene Complexes;42
1.7.1.1.1.1.4.3;1.4.5.1.1.4.3 Variation 3: Synthesis of (.5-Cyclopentadienyl)(triphenylphosphine)cobalt–N-Heterocyclic Carbene Complexes;42
1.7.1.1.1.1.5;1.4.5.1.1.5 Method 5: Synthesis of (.5-Cyclopentadienyl)(phosphine)cobalt(I)–Ligand Complexes;43
1.7.1.1.1.1.5.1;1.4.5.1.1.5.1 Variation 1: Synthesis of Carbonyl(.5-cyclopentadienyl)(triphenylphosphine)cobalt(I);43
1.7.1.1.1.1.5.2;1.4.5.1.1.5.2 Variation 2: Synthesis of (.5-Cyclopentadienyl)(triphenylphosphine)cobalt(I)–Alkene Complexes;43
1.7.1.1.1.1.5.3;1.4.5.1.1.5.3 Variation 3: Synthesis of {[2-(Di-tert-butylphosphino)ethyl]cyclopentadienyl}(ethene)cobalt(I);44
1.7.1.1.1.1.6;1.4.5.1.1.6 Method 6: Synthesis of (.5-Cyclopentadienyl)cobalt–Dinitrosoalkane Complexes;45
1.7.1.1.1.1.7;1.4.5.1.1.7 Method 7: Synthesis of (.5-Pentamethylcyclopentadienyl)cobalt–.3-Allyl Complexes by Exchange of Ligands;46
1.7.1.1.1.1.8;1.4.5.1.1.8 Method 8: Synthesis of (.5-Cyclopentadienyl)cobalt–.5-Pentadienyl Complexes by Exchange of Ligands;48
1.7.1.1.1.1.9;1.4.5.1.1.9 Method 9: Synthesis of (.5-Cyclopentadienyl)cobalt–Alkyne Complexes;50
1.7.1.1.1.1.10;1.4.5.1.1.10 Method 10: Synthesis of (.5-Cyclopentadienyl)cobaltacycles;51
1.7.1.1.1.1.10.1;1.4.5.1.1.10.1 Variation 1: Synthesis of (.5-Cyclopentadienyl)cobaltacyclobutenes;51
1.7.1.1.1.1.10.2;1.4.5.1.1.10.2 Variation 2: Synthesis of (.5-Cyclopentadienyl)cobaltasilacyclopentenes;51
1.7.1.1.1.2;1.4.5.1.2 Applications of Cobalt–.5-Dienyl Complexes in Organic Synthesis;52
1.7.1.1.1.2.1;1.4.5.1.2.1 Method 1: Inter- and Intramolecular [2 + 2 + 2] Cyclizations;52
1.7.1.1.1.2.1.1;1.4.5.1.2.1.1 Variation 1: Inter- and Intramolecular [2 + 2 + 2] Cyclizations of Triynes in Aromatic and Aqueous Solvents;52
1.7.1.1.1.2.1.2;1.4.5.1.2.1.2 Variation 2: Intermolecular [2 + 2 + 2] Cyclizations of Diynes and Nitriles: Preparation of Pyridines;59
1.7.1.1.1.2.1.3;1.4.5.1.2.1.3 Variation 3: Intermolecular [2 + 2 + 2] Cyclizations of Enediynes and Allenediynes;63
1.7.1.1.1.2.1.4;1.4.5.1.2.1.4 Variation 4: Inter- and Intramolecular [2 + 2 + 2] Cyclizations of Diynes with Heteroatom-Substituted Multiple Bonds;67
1.7.1.1.1.2.2;1.4.5.1.2.2 Method 2: Other Cyclizations;67
1.7.1.1.1.2.2.1;1.4.5.1.2.2.1 Variation 1: [2 + 2] Cycloaddition;68
1.7.1.1.1.2.2.2;1.4.5.1.2.2.2 Variation 2: [3 + 2] Annulation;69
1.7.1.1.1.2.2.3;1.4.5.1.2.2.3 Variation 3: [3 + 2 + 2] Cycloaddition;70
1.7.1.1.1.2.2.4;1.4.5.1.2.2.4 Variation 4: [5 + 2] Cycloaddition;72
1.7.1.1.1.2.3;1.4.5.1.2.3 Method 3: Miscellaneous Reactions;73
1.7.1.1.1.2.3.1;1.4.5.1.2.3.1 Variation 1: Cobalt-Mediated Ring Expansion;73
1.7.1.1.1.2.3.2;1.4.5.1.2.3.2 Variation 2: Linear Co-oligomerization of Alkynes with Alkenes;74
1.7.1.1.1.2.3.3;1.4.5.1.2.3.3 Variation 3: Hydroamination of Alkynes;76
1.7.1.1.1.2.3.4;1.4.5.1.2.3.4 Variation 4: Activation of sp3 C--H Bonds;77
1.7.1.1.1.2.3.5;1.4.5.1.2.3.5 Variation 5: Vinylic C--H Functionalization Reactions;78
1.7.1.1.2;1.4.5.2 Miscellaneous Cobalt Complexes;79
1.7.1.1.2.1;1.4.5.2.1 Synthesis of Miscellaneous Cobalt Complexes;79
1.7.1.1.2.1.1;1.4.5.2.1.1 Method 1: Synthesis of Methyltetrakis(trimethylphosphine)cobalt(I);79
1.7.1.1.2.1.2;1.4.5.2.1.2 Method 2: Synthesis of Chlorotris(trimethylphosphine)cobalt(I);80
1.7.1.1.2.1.3;1.4.5.2.1.3 Method 3: Synthesis of Dihalobis(phosphine)cobalt(II) Complexes;80
1.7.1.1.2.1.4;1.4.5.2.1.4 Method 4: Cobalt(II) or -(III) Salts as Precatalysts;81
1.7.1.1.2.1.5;1.4.5.2.1.5 Method 5: Preformed Cobalt(II) and Cobalt(III) Complexes;82
1.7.1.1.2.2;1.4.5.2.2 Applications of Miscellaneous Cobalt Complexes in Organic Synthesis;83
1.7.1.1.2.2.1;1.4.5.2.2.1 Method 1: Cobalt-Catalyzed Homocoupling Reactions;83
1.7.1.1.2.2.2;1.4.5.2.2.2 Method 2: C(sp2)--C(sp2) Cross-Coupling Reactions;84
1.7.1.1.2.2.2.1;1.4.5.2.2.2.1 Variation 1: Alkenylation;85
1.7.1.1.2.2.2.2;1.4.5.2.2.2.2 Variation 2: Biaryl Formation;86
1.7.1.1.2.2.3;1.4.5.2.2.3 Method 3: C(sp2)--C(sp3) Cross-Coupling Reactions;88
1.7.1.1.2.2.3.1;1.4.5.2.2.3.1 Variation 1: Alkylation of Alkenyl Halides;88
1.7.1.1.2.2.3.2;1.4.5.2.2.3.2 Variation 2: Alkenylation of Alkyl Halides;89
1.7.1.1.2.2.3.3;1.4.5.2.2.3.3 Variation 3: Alkylation of Aromatic Halides;90
1.7.1.1.2.2.3.4;1.4.5.2.2.3.4 Variation 4: Arylation of Alkyl Halides;90
1.7.1.1.2.2.3.5;1.4.5.2.2.3.5 Variation 5: Pseudodirect and Direct Arylation of Alkyl Halides;92
1.7.1.1.2.2.3.6;1.4.5.2.2.3.6 Variation 6: Allylation;94
1.7.1.1.2.2.4;1.4.5.2.2.4 Method 4: C(sp3)--C(sp3) Cross-Coupling Reactions;95
1.7.1.1.2.2.4.1;1.4.5.2.2.4.1 Variation 1: Allylation;95
1.7.1.1.2.2.4.2;1.4.5.2.2.4.2 Variation 2: Benzylation;96
1.7.1.1.2.2.4.3;1.4.5.2.2.4.3 Variation 3: Alkylation;96
1.7.1.1.2.2.5;1.4.5.2.2.5 Method 5: Alkynylation;97
1.7.1.1.2.2.5.1;1.4.5.2.2.5.1 Variation 1: Benzylation of Alkynes;97
1.7.1.1.2.2.5.2;1.4.5.2.2.5.2 Variation 2: Alkylation of Alkynes;97
1.7.1.1.2.2.5.3;1.4.5.2.2.5.3 Variation 3: Alkenylation of Alkynes;98
1.7.1.1.2.2.6;1.4.5.2.2.6 Method 6: Acylation;98
1.7.1.1.2.2.7;1.4.5.2.2.7 Method 7: Radical Reactions;99
1.7.1.1.2.2.8;1.4.5.2.2.8 Method 8: Cross Coupling of Unsaturated Compounds;101
1.7.1.1.2.2.8.1;1.4.5.2.2.8.1 Variation 1: Alkyne Functionalization;101
1.7.1.1.2.2.8.2;1.4.5.2.2.8.2 Variation 2: Cross Coupling of Alkynes with Enones;101
1.7.1.1.2.2.8.3;1.4.5.2.2.8.3 Variation 3: Cross-Coupling Reactions Involving Alkenes and Alkynes;103
1.7.1.1.2.2.9;1.4.5.2.2.9 Method 9: Michael-Type Conjugate Additions;103
1.7.1.1.2.2.10;1.4.5.2.2.10 Method 10: Formation of Carbon--Heteroatom Bonds;104
1.7.1.1.2.2.11;1.4.5.2.2.11 Method 11: Cross-Coupling Reactions with Carbonyl Compounds;105
1.7.1.1.2.2.11.1;1.4.5.2.2.11.1 Variation 1: Allylation;105
1.7.1.1.2.2.11.2;1.4.5.2.2.11.2 Variation 2: Formation of Hydroxy Amides and Esters;106
1.7.1.1.2.2.11.3;1.4.5.2.2.11.3 Variation 3: Arylation;106
1.7.1.1.2.2.12;1.4.5.2.2.12 Method 12: Multicomponent Reactions;107
1.7.1.1.2.2.13;1.4.5.2.2.13 Method 13: Preparation of Organometallic Derivatives;108
1.7.1.1.2.2.14;1.4.5.2.2.14 Method 14: Cyclization Reactions;109
1.7.1.1.2.2.15;1.4.5.2.2.15 Method 15: Cobalt-Catalyzed Cycloadditions;110
1.7.1.1.2.2.15.1;1.4.5.2.2.15.1 Variation 1: [2 + 2] Cycloadditions;110
1.7.1.1.2.2.15.2;1.4.5.2.2.15.2 Variation 2: [3 + 2] Cycloadditions;111
1.7.1.1.2.2.15.3;1.4.5.2.2.15.3 Variation 3: [4 + 2] Cycloadditions;112
1.7.1.1.2.2.15.4;1.4.5.2.2.15.4 Variation 4: Homo-Diels–Alder Reactions;115
1.7.1.1.2.2.15.5;1.4.5.2.2.15.5 Variation 5: [6 + 2] Cycloadditions;116
1.7.1.1.2.2.15.6;1.4.5.2.2.15.6 Variation 6: [2 + 2 + 2] Cycloadditions;116
1.7.1.1.2.2.15.7;1.4.5.2.2.15.7 Variation 7: [4 + 2 + 2] Cycloadditions;120
1.7.1.1.2.2.15.8;1.4.5.2.2.15.8 Variation 8: [6 + 4] Cycloadditions;121
1.7.1.1.2.2.15.9;1.4.5.2.2.15.9 Variation 9: Dipolar Cycloadditions with Nitrones;122
1.7.1.1.2.2.16;1.4.5.2.2.16 Method 16: Alkene Functionalizations;123
1.7.1.1.2.2.16.1;1.4.5.2.2.16.1 Variation 1: Cyclopropanation;123
1.7.1.1.2.2.16.2;1.4.5.2.2.16.2 Variation 2: Aziridination;127
1.7.1.1.2.2.16.3;1.4.5.2.2.16.3 Variation 3: Hydrovinylation of Alkenes;129
1.7.1.1.2.2.16.4;1.4.5.2.2.16.4 Variation 4: Miscellaneous Alkene Functionalizations;130
1.7.1.1.2.2.17;1.4.5.2.2.17 Method 17: C--H Activation;131
1.7.1.1.2.2.17.1;1.4.5.2.2.17.1 Variation 1: Cobalt-Catalyzed Assisted ortho-Functionalization;131
1.7.1.1.2.2.17.2;1.4.5.2.2.17.2 Variation 2: Cobalt-Catalyzed Direct Arylation;134
1.7.1.1.2.2.17.3;1.4.5.2.2.17.3 Variation 3: Cobalt-Catalyzed Transformation of Alkynyl C--H Bonds;135
1.7.1.1.2.2.17.4;1.4.5.2.2.17.4 Variation 4: Cobalt-Catalyzed C--H Amination;135
1.7.1.1.2.2.17.5;1.4.5.2.2.17.5 Variation 5: Formation of Organocobalt Complexes;136
1.7.1.1.2.2.18;1.4.5.2.2.18 Method 18: Cobalt-Catalyzed Ring-Expansion and Ring-Opening Reactions;141
1.7.1.1.2.2.18.1;1.4.5.2.2.18.1 Variation 1: Cobalt-Catalyzed Carboxylative and Carbonylative Ring Expansion/Opening;142
1.7.1.1.2.2.18.2;1.4.5.2.2.18.2 Variation 2: Cobalt-Catalyzed Ring-Opening Reactions;144
1.8;Volume 3: Compounds of Groups 12 and 11 (Zn, Cd, Hg, Cu, Ag, Au);158
1.8.1;3.6 Product Class 6: Organometallic Complexes of Gold;158
1.8.1.1;3.6.14 Organometallic Complexes of Gold (Update 1);158
1.8.1.1.1;3.6.14.1 Asymmetric Gold-Catalyzed Transformations;158
1.8.1.1.1.1;3.6.14.1.1 Asymmetric Gold(I)-Catalyzed Transformations Proceeding via Initial Alkyne p-Activation;163
1.8.1.1.1.1.1;3.6.14.1.1.1 Cycloisomerization Reactions;163
1.8.1.1.1.1.1.1;3.6.14.1.1.1.1 Method 1: Cycloisomerizations of 1,6-Enynes;163
1.8.1.1.1.1.1.1.1;3.6.14.1.1.1.1.1 Variation 1: 5-exo-dig Cyclization;163
1.8.1.1.1.1.1.1.2;3.6.14.1.1.1.1.2 Variation 2: 6-endo-dig Cyclization;166
1.8.1.1.1.1.1.2;3.6.14.1.1.1.2 Method 2: Cycloisomerizations of 1,5-Enynes;170
1.8.1.1.1.1.1.3;3.6.14.1.1.1.3 Method 3: Cyclizations of 1,3-Enynes;171
1.8.1.1.1.1.1.4;3.6.14.1.1.1.4 Method 4: Cyclopropanations;172
1.8.1.1.1.1.1.4.1;3.6.14.1.1.1.4.1 Variation 1: Intermolecular Cyclopropanation;172
1.8.1.1.1.1.1.4.2;3.6.14.1.1.1.4.2 Variation 2: Intramolecular Cyclopropanation;174
1.8.1.1.1.1.1.5;3.6.14.1.1.1.5 Method 5: Analogous Cycloisomerizations Proceeding through Gold(I) Carbenoids;175
1.8.1.1.1.1.1.6;3.6.14.1.1.1.6 Method 6: Other Cycloisomerization Reactions of Propargyl Carboxylates;176
1.8.1.1.1.1.2;3.6.14.1.1.2 Desymmetrization Reactions;177
1.8.1.1.1.1.2.1;3.6.14.1.1.2.1 Method 1: Desymmetrization of Diynes;177
1.8.1.1.1.1.2.2;3.6.14.1.1.2.2 Method 2: Desymmetrization of Diols;179
1.8.1.1.1.2;3.6.14.1.2 Asymmetric Gold(I)-Catalyzed Transformations Proceeding via Initial Allene p-Activation;180
1.8.1.1.1.2.1;3.6.14.1.2.1 Cycloisomerization Reactions;180
1.8.1.1.1.2.1.1;3.6.14.1.2.1.1 Method 1: Hydroindolization;180
1.8.1.1.1.2.1.2;3.6.14.1.2.1.2 Method 2: Cycloisomerization of 1,6-Allenenes;181
1.8.1.1.1.2.1.3;3.6.14.1.2.1.3 Method 3: Formal [2 + 2]-Cycloaddition Reactions;182
1.8.1.1.1.2.1.4;3.6.14.1.2.1.4 Method 4: Formal [4 + 2]-Cycloaddition Reactions;184
1.8.1.1.1.2.1.5;3.6.14.1.2.1.5 Method 5: Ring Expansion of Allenylcyclopropanols;186
1.8.1.1.1.2.2;3.6.14.1.2.2 Addition Reactions;187
1.8.1.1.1.2.2.1;3.6.14.1.2.2.1 Method 1: Intramolecular Hydroalkoxylation and Hydroamination;187
1.8.1.1.1.2.2.2;3.6.14.1.2.2.2 Method 2: Intramolecular Hydroindolization;196
1.8.1.1.1.2.2.3;3.6.14.1.2.2.3 Method 3: Intermolecular Hydroamination;197
1.8.1.1.1.3;3.6.14.1.3 Asymmetric Reactions of Alkenes;198
1.8.1.1.1.3.1;3.6.14.1.3.1 Method 1: Hydrogenation;198
1.8.1.1.1.4;3.6.14.1.4 Miscellaneous Reactions;199
1.8.1.1.1.4.1;3.6.14.1.4.1 Method 1: Enantioselective Reactions by Lewis Acidic Heteroatom Coordination;199
1.8.1.1.1.4.1.1;3.6.14.1.4.1.1 Variation 1: Aldol Reaction;199
1.8.1.1.1.4.1.2;3.6.14.1.4.1.2 Variation 2: Cycloaddition of Münchnones with Electron-Deficient Alkenes;199
1.8.1.1.1.4.2;3.6.14.1.4.2 Method 2: Enantioselective Reactions of Alkynyl–Gold(I) Species;200
1.8.1.1.1.4.3;3.6.14.1.4.3 Method 3: Enantioselective Protonation of Silyl Enol Ethers;201
1.8.1.2;3.6.15 Organometallic Complexes of Gold (Update 2);206
1.8.1.2.1;3.6.15.1 Gold-Catalyzed Reactions of Alkenes;206
1.8.1.2.1.1;3.6.15.1.1 Functionalization of Alkenes;206
1.8.1.2.1.1.1;3.6.15.1.1.1 Hydrofunctionalization of Unactivated Alkenes;206
1.8.1.2.1.1.1.1;3.6.15.1.1.1.1 Method 1: Inter- and Intramolecular Hydroalkylation of Alkenes;206
1.8.1.2.1.1.1.2;3.6.15.1.1.1.2 Method 2: Inter- and Intramolecular Hydroarylation of Alkenes;209
1.8.1.2.1.1.1.2.1;3.6.15.1.1.1.2.1 Variation 1: Formation of Hexahydrodibenzo[b,d]furans;211
1.8.1.2.1.1.1.3;3.6.15.1.1.1.3 Method 3: Hydroalkoxylation of Alkenes;211
1.8.1.2.1.1.1.3.1;3.6.15.1.1.1.3.1 Variation 1: Formation of Allylic Ethers;213
1.8.1.2.1.1.1.3.2;3.6.15.1.1.1.3.2 Variation 2: Formation of Dihydrobenzofurans from Allyl Aryl Ethers;214
1.8.1.2.1.1.1.4;3.6.15.1.1.1.4 Method 4: Inter- and Intramolecular Hydroamination of Alkenes;215
1.8.1.2.1.1.1.4.1;3.6.15.1.1.1.4.1 Variation 1: Formation of Pyrrolidines through Domino Ring Opening/Ring Closing of Methylenecyclopropanes with Sulfonamides;221
1.8.1.2.1.1.1.4.2;3.6.15.1.1.1.4.2 Variation 2: Inter- and Intramolecular Hydroamination of Dienes;222
1.8.1.2.1.1.1.5;3.6.15.1.1.1.5 Method 5: Hydrothiolation of Alkenes;224
1.8.1.2.1.1.2;3.6.15.1.1.2 Michael-Type Addition to a,ß-Unsaturated Carbonyl Compounds;225
1.8.1.2.1.1.2.1;3.6.15.1.1.2.1 Method 1: Addition of Indoles and 7-Azaindoles to a,ß-Unsaturated Ketones;226
1.8.1.2.1.1.2.1.1;3.6.15.1.1.2.1.1 Variation 1: Formation of Alkylated Indoles from 2-Alkynylanilines;228
1.8.1.2.1.1.2.2;3.6.15.1.1.2.2 Method 2: Addition of Furans and Pyrroles to a,ß-Unsaturated Ketones;229
1.8.1.2.1.1.2.2.1;3.6.15.1.1.2.2.1 Variation 1: Formation of Phenols from Furans and a,ß-Unsaturated Alkynyl Ketones;230
1.8.1.2.1.1.2.3;3.6.15.1.1.2.3 Method 3: Addition of Electron-Rich Arenes to a,ß-Unsaturated Carbonyl Compounds and Nitriles;230
1.8.1.2.1.1.2.4;3.6.15.1.1.2.4 Method 4: Addition of Carbamates and 4-Toluenesulfonamides to a,ß-Unsaturated Ketones;231
1.8.1.2.1.1.3;3.6.15.1.1.3 Reactions of Allylic Acetates;232
1.8.1.2.1.1.3.1;3.6.15.1.1.3.1 Method 1: Rearrangement of Allylic Acetates;233
1.8.1.2.1.1.3.2;3.6.15.1.1.3.2 Method 2: Allyl–Allyl Coupling;235
1.8.1.2.1.1.3.3;3.6.15.1.1.3.3 Method 3: Cascade Intermolecular Allylic Substitution/Enyne Cycloisomerization;236
1.8.1.2.1.1.4;3.6.15.1.1.4 Intermolecular Cyclopropanation of Alkenes;236
1.8.1.2.1.1.4.1;3.6.15.1.1.4.1 Method 1: Cyclopropanation via Transfer Reaction from Diazo Compounds;237
1.8.1.2.1.1.4.2;3.6.15.1.1.4.2 Method 2: Cyclopropanation via In Situ Generated Gold Carbenes from Propargylic Acetates;240
1.8.1.2.1.1.4.2.1;3.6.15.1.1.4.2.1 Variation 1: Cyclopropanation via Retro-Buchner Reaction;242
1.8.1.2.1.1.5;3.6.15.1.1.5 Cycloaddition Reactions;243
1.8.1.2.1.1.5.1;3.6.15.1.1.5.1 Method 1: Intermolecular [3 + 2] Cycloaddition of Alkynyl Epoxides with Alkenes;244
1.8.1.2.1.1.5.1.1;3.6.15.1.1.5.1.1 Variation 1: Formation of Tricyclic Indoles from Azomethine Ylides;244
1.8.1.2.1.1.5.2;3.6.15.1.1.5.2 Method 2: Intermolecular [4 + 2] Cycloaddition of Enynes and Alkynes;245
1.8.1.2.1.1.5.2.1;3.6.15.1.1.5.2.1 Variation 1: Formation of Benzonorcaradienes by Intermolecular [4 + 3] Cycloaddition of Diynes and Alkenes;247
1.8.1.2.1.1.5.3;3.6.15.1.1.5.3 Method 3: Intermolecular [3 + 2] and [4 + 3] Cycloadditions of Propargyl Carboxylates and Alkenes or Dienes;248
1.8.1.2.1.1.5.4;3.6.15.1.1.5.4 Method 4: 1,3-Dipolar Cycloadditions;252
1.8.1.2.1.1.5.4.1;3.6.15.1.1.5.4.1 Variation 1: Enantioselective 1,3-Dipolar Cycloadditions of Münchnones;253
1.8.1.2.1.1.6;3.6.15.1.1.6 Oxidation of Alkenes;255
1.8.1.2.1.1.6.1;3.6.15.1.1.6.1 Method 1: Formation of Carbonyl Compounds;255
1.9;Volume 6: Boron Compounds;262
1.9.1;6.1 Product Class 1: Boron Compounds;262
1.9.1.1;6.1.3.8 Diborane(4) Compounds;262
1.9.1.1.1;6.1.3.8.1 Applications of Diborane(4) Compounds in Organic Synthesis;262
1.9.1.1.1.1;6.1.3.8.1.1 Method 1: Diboration of Alkenes;262
1.9.1.1.1.1.1;6.1.3.8.1.1.1 Variation 1: Enantioselective Diboration of Terminal Alkenes;262
1.9.1.1.1.1.2;6.1.3.8.1.1.2 Variation 2: Metal-Free Diboration;263
1.9.1.1.1.2;6.1.3.8.1.2 Method 2: Enantioselective Diboration of Allenes;264
1.9.1.1.1.3;6.1.3.8.1.3 Method 3: Enantioselective Diboration of (E)-1,3-Dienes;265
1.9.1.1.1.4;6.1.3.8.1.4 Method 4: Advances in Alkyne Hydroboration and Diboration;266
1.9.1.1.1.4.1;6.1.3.8.1.4.1 Variation 1: N-Heterocyclic Carbene–Copper Catalyzed Dihydroboration of Terminal Alkynes;266
1.9.1.1.1.4.2;6.1.3.8.1.4.2 Variation 2: Borylative Cyclization of Enynes;267
1.9.1.1.1.4.3;6.1.3.8.1.4.3 Variation 3: Platinum-Catalyzed Diborylation of Arynes;268
1.9.1.1.1.4.4;6.1.3.8.1.4.4 Variation 4: Differentially Protected Diboron Reagents;269
1.9.1.1.1.5;6.1.3.8.1.5 Method 5: Allylic Substitution;271
1.9.1.1.1.5.1;6.1.3.8.1.5.1 Variation 1: Nickel-Catalyzed Borylative Ring Opening of Vinyl Epoxides and Aziridines;271
1.9.1.1.1.5.2;6.1.3.8.1.5.2 Variation 2: Reaction Using a Copper(I)–Bidentate Phosphine Complex;272
1.9.1.1.1.5.3;6.1.3.8.1.5.3 Variation 3: Reaction Using a Copper(II)–N-Heterocyclic Carbene Complex;273
1.9.1.1.1.5.4;6.1.3.8.1.5.4 Variation 4: Desymmetrization of meso-Diols;275
1.9.1.1.1.6;6.1.3.8.1.6 Method 6: Copper-Catalyzed Synthesis of Multisubstituted Allenylboronates;276
1.9.1.1.1.7;6.1.3.8.1.7 Method 7: Nickel-Catalyzed Borylative Ring Opening;277
1.9.1.1.1.7.1;6.1.3.8.1.7.1 Variation 1: Reaction of Vinylcyclopropanes;277
1.9.1.1.1.7.2;6.1.3.8.1.7.2 Variation 2: Reaction of Aryl Cyclopropyl Ketones;277
1.9.1.1.1.8;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
1.9.1.1.1.8.1;6.1.3.8.1.8.1 Variation 1: Racemic Addition to Carbonyl Compounds;279
1.9.1.1.1.8.2;6.1.3.8.1.8.2 Variation 2: Enantioselective Addition to Carbonyl Compounds;280
1.9.1.1.1.8.3;6.1.3.8.1.8.3 Variation 3: Addition to Aldehydes and Imines;281
1.9.1.1.1.8.4;6.1.3.8.1.8.4 Variation 4: Metal-Free Addition to Carbonyl Compounds;283
1.9.1.1.1.8.5;6.1.3.8.1.8.5 Variation 5: Tertiary Boronic Esters by Addition to 3,3-Disubstituted Enones;284
1.9.1.1.1.8.6;6.1.3.8.1.8.6 Variation 6: Enantioselective Addition to 3-Boryl Enoates;285
1.9.1.1.1.9;6.1.3.8.1.9 Method 9: Synthesis of Cycloalkylboronates;288
1.9.1.1.1.9.1;6.1.3.8.1.9.1 Variation 1: Stereospecific Synthesis of Cyclobutylboronates;288
1.9.1.1.1.9.2;6.1.3.8.1.9.2 Variation 2: Enantioselective Synthesis of Cyclopropylboronates;288
1.9.1.1.2;6.1.35.20 Allylboranes;292
1.9.1.1.2.1;6.1.35.20.1 Synthesis of Allylboranes;292
1.9.1.1.2.1.1;6.1.35.20.1.1 Method 1: Synthesis by Transmetalation;292
1.9.1.1.2.1.2;6.1.35.20.1.2 Method 2: Synthesis by Hydroboration of 1,3-Dienes or Allenes;300
1.9.1.1.2.1.2.1;6.1.35.20.1.2.1 Variation 1: Catalyzed Hydroboration of 1,3-Dienes;300
1.9.1.1.2.1.2.2;6.1.35.20.1.2.2 Variation 2: Thermal Hydroboration;302
1.9.1.1.2.1.3;6.1.35.20.1.3 Method 3: Synthesis by Diboration or Silaboration of 1,3-Dienes, Allenes, or Vinylcyclopropanes;307
1.9.1.1.2.1.3.1;6.1.35.20.1.3.1 Variation 1: Diboration of 1,3-Dienes, Enones, or Allenes;307
1.9.1.1.2.1.3.2;6.1.35.20.1.3.2 Variation 2: Diboration of Vinylcyclopropanes, Vinyloxiranes, or Aziridines;315
1.9.1.1.2.1.3.3;6.1.35.20.1.3.3 Variation 3: Silaboration of 1,3-Dienes or Allenes;317
1.9.1.1.2.1.4;6.1.35.20.1.4 Method 4: Synthesis by [4 + 2] Cycloaddition;319
1.9.1.1.2.1.5;6.1.35.20.1.5 Method 5: Synthesis from Diborane(4) Derivatives and Allylic Alcohols, Acetates, or Carbonates;322
1.9.1.1.2.1.6;6.1.35.20.1.6 Method 6: Synthesis by 3,3-Sigmatropic Rearrangement;328
1.9.1.1.2.1.7;6.1.35.20.1.7 Method 7: Homologation of Alkenylboron Compounds;331
1.9.1.1.2.1.8;6.1.35.20.1.8 Method 8: Synthesis by Vinylation of (a-Haloalkyl)boron Derivatives;335
1.9.1.1.2.1.9;6.1.35.20.1.9 Method 9: Synthesis by Metathesis;338
1.9.1.1.2.1.10;6.1.35.20.1.10 Method 10: Synthesis by Miscellaneous Methods;342
1.9.1.1.2.2;6.1.35.20.2 Applications of Allylboranes in Organic Synthesis;351
1.9.1.1.2.2.1;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
1.9.1.1.2.2.1.1;6.1.35.20.2.1.1 Variation 1: Allylboration of Aldehydes and Ketones;352
1.9.1.1.2.2.1.2;6.1.35.20.2.1.2 Variation 2: Allylboration of C==N Bonds;355
1.9.1.1.2.2.2;6.1.35.20.2.2 Method 2: Allylboration of N==N and C==N Bonds;359
1.9.1.1.2.2.3;6.1.35.20.2.3 Method 3: Allylation by Cross-Coupling Reactions;360
1.9.1.1.2.2.4;6.1.35.20.2.4 Method 4: Allylboron–Acetylene Condensation;364
1.9.1.1.2.2.5;6.1.35.20.2.5 Method 5: Reductive trans-Diallylation of Aromatic N-Heterocycles;367
1.9.1.1.2.2.6;6.1.35.20.2.6 Method 6: Miscellaneous Methods;369
1.10;Volume 16: Six-Membered Hetarenes with Two Identical Heteroatoms;378
1.10.1;16.15 Product Class 15: Quinoxalines;378
1.10.1.1;16.15.5 Quinoxalines;378
1.10.1.1.1;16.15.5.1 Synthesis by Ring-Closure Reactions;380
1.10.1.1.1.1;16.15.5.1.1 By Annulation to an Arene;380
1.10.1.1.1.1.1;16.15.5.1.1.1 By Formation of Two N--C Bonds and One C--C Bond;380
1.10.1.1.1.1.1.1;16.15.5.1.1.1.1 Fragments N--Arene--N, C, and C;380
1.10.1.1.1.1.1.1.1;16.15.5.1.1.1.1.1 Method 1: From Benzene-1,2-diamine, Aldehydes, and Isocyanides;380
1.10.1.1.1.1.1.1.2;16.15.5.1.1.1.1.2 Method 2: From Benzene-1,2-diamine, Aldehydes, and Tosylmethyl Isocyanide;381
1.10.1.1.1.1.2;16.15.5.1.1.2 By Formation of Two N--C Bonds;382
1.10.1.1.1.1.2.1;16.15.5.1.1.2.1 Fragments N--Arene--N and C--C;382
1.10.1.1.1.1.2.1.1;16.15.5.1.1.2.1.1 Method 1: From Benzene-1,2-diamines and Glyoxal or Its Synthetic Equivalents;383
1.10.1.1.1.1.2.1.1.1;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
1.10.1.1.1.1.2.1.1.2;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
1.10.1.1.1.1.2.1.1.3;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
1.10.1.1.1.1.2.1.1.4;16.15.5.1.1.2.1.1.4 Variation 4: From Benzene-1,2-diamine and N,N'-Dicyclohexylethane-1,2-diimine;385
1.10.1.1.1.1.2.1.2;16.15.5.1.1.2.1.2 Method 2: From Benzene-1,2-diamines and a-Oxoaldehydes or Their Synthetic Equivalents;385
1.10.1.1.1.1.2.1.2.1;16.15.5.1.1.2.1.2.1 Variation 1: From Benzene-1,2-diamine and a,a-Dihydroxy Ketones;386
1.10.1.1.1.1.2.1.2.2;16.15.5.1.1.2.1.2.2 Variation 2: From Benzene-1,2-diamine and a-Ketoaldehyde Oximes or Hydrazones;386
1.10.1.1.1.1.2.1.3;16.15.5.1.1.2.1.3 Method 3: From Benzene-1,2-diamines and 1,2-Diketones or Their Synthetic Equivalents;387
1.10.1.1.1.1.2.1.3.1;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
1.10.1.1.1.1.2.1.3.2;16.15.5.1.1.2.1.3.2 Variation 2: From Benzene-1,2-diamines and Alkynes under Oxidative Conditions;389
1.10.1.1.1.1.2.1.3.3;16.15.5.1.1.2.1.3.3 Variation 3: From Benzene-1,2-diamines and Diiminosuccinonitrile;389
1.10.1.1.1.1.2.1.4;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
1.10.1.1.1.1.2.1.5;16.15.5.1.1.1.1.5 Method 5: From Benzene-1,2-diamines and Oxalic Acid Derivatives;391
1.10.1.1.1.1.2.1.5.1;16.15.5.1.1.1.1.5.1 Variation 1: From Benzene-1,2-diamines and Alkyl Alkoxy(imino)acetates;392
1.10.1.1.1.1.2.1.6;16.15.5.1.1.2.1.6 Method 6: From Benzene-1,2-diamines and Dialkyl Acetylenedicarboxylates;393
1.10.1.1.1.1.2.1.7;16.15.5.1.1.2.1.7 Method 7: From Benzene-1,2-diamine and Aryl Methyl Ketones and Their Derivatives;394
1.10.1.1.1.1.2.1.7.1;16.15.5.1.1.2.1.7.1 Variation 1: Oxidative Cyclization of Benzene-1,2-diamine and Acetylpyridines;394
1.10.1.1.1.1.2.1.7.2;16.15.5.1.1.2.1.7.2 Variation 2: From Benzene-1,2-diamines and Hydroxymethyl Ketones;395
1.10.1.1.1.1.2.1.7.3;16.15.5.1.1.2.1.7.3 Variation 3: From Benzene-1,2-diamines and Halomethyl Ketones;396
1.10.1.1.1.1.2.1.7.4;16.15.5.1.1.2.1.7.4 Variation 4: From Benzene-1,2-diamines and Aminomethyl Ketones;397
1.10.1.1.1.1.2.1.8;16.15.5.1.1.2.1.8 Method 8: From Benzene-1,2-diamines and a-Diazo Ketones;397
1.10.1.1.1.1.2.2;16.15.5.1.1.2.2 Fragments N--C--C--N and C--C (Arene);398
1.10.1.1.1.1.2.2.1;16.15.5.1.1.2.2.1 Method 1: From 1,2-Diamines and Benzo-1,4-quinones and -1,2-quinones;398
1.10.1.1.1.1.2.3;16.15.5.1.1.2.3 Fragments N--Arene and N--C--C;398
1.10.1.1.1.1.2.3.1;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
1.10.1.1.1.1.3;16.15.5.1.1.3 By Formation of One N--C and One C--C Bond;399
1.10.1.1.1.1.4;16.15.5.1.1.4 By Formation of One N--C Bond;400
1.10.1.1.1.1.4.1;16.15.5.1.1.4.1 Fragment N--Arene--N--C--C;400
1.10.1.1.1.1.4.1.1;16.15.5.1.1.4.1.1 Method 1: Intramolecular Reactions of C-Electrophiles with a 2-Aminophenyl Group;400
1.10.1.1.1.1.4.1.1.1;16.15.5.1.1.4.1.1.1 Variation 1: Intramolecular Reductive Cyclization of N-(2-Nitrophenyl)-2-oxopropanamide;400
1.10.1.1.1.1.4.1.1.2;16.15.5.1.1.4.1.1.2 Variation 2: From N-(2-Nitrophenyl)glycines by a Reductive Cyclization/Oxidation Sequence;400
1.10.1.1.1.1.4.1.1.3;16.15.5.1.1.4.1.1.3 Variation 3: Intramolecular Reductive Cyclization of 2-(2-Nitrophenylamino)-2-oxoacetates;401
1.10.1.1.1.1.4.1.2;16.15.5.1.1.4.1.2 Method 2: Quinoxalinone N-Oxides by Intramolecular C-Nucleophilic Attack on a 2-Nitrophenyl Group;402
1.10.1.1.1.1.4.2;16.15.5.1.1.4.2 Fragment Arene--N--C--C--N;403
1.10.1.1.1.1.4.2.1;16.15.5.1.1.4.2.1 Method 1: Intramolecular Cyclization of (Phenylimino)acetaldehyde;403
1.10.1.1.1.1.4.2.2;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
1.10.1.1.1.2;16.15.5.1.2 By Annulation to the Heterocyclic Ring;404
1.10.1.1.1.2.1;16.15.5.1.2.1 By Formation of Two C--C Bonds;404
1.10.1.1.1.2.1.1;16.15.5.1.2.1.1 Fragments C--Hetarene--C and C--C;404
1.10.1.1.1.2.1.1.1;16.15.5.1.2.1.1.1 Method 1: Cycloaddition of 2,3-Bis(dibromomethyl)pyrazine to Dienophiles;404
1.10.1.1.2;16.15.5.2 Synthesis by Ring Transformation;404
1.10.1.1.2.1;16.15.5.2.1 By Ring Enlargement;404
1.10.1.1.2.1.1;16.15.5.2.1.1 Method 1: From Benzimidazoles and 1,2-Diketones;404
1.10.1.1.2.1.2;16.15.5.2.1.2 Method 2: Quinoxalines from Benzofurazans and 2-Aminoethanol;405
1.10.1.1.2.1.3;16.15.5.2.1.3 Method 3: Quinoxaline 1,4-Dioxides from Benzofurazan 1-Oxides and Enolizable Carbonyl Compounds;405
1.10.1.1.2.1.4;16.15.5.2.1.4 Method 4: From Benzene-1,2-diamines and 1H-Indole-2,3-diones (Isatins);406
1.10.1.1.3;16.15.5.3 Synthesis by Ring Modification;407
1.10.1.1.3.1;16.15.5.3.1 Oxidative Ring Modifications;407
1.10.1.1.3.1.1;16.15.5.3.1.1 Method 1: Aromatization by Oxidation of 1,2,3,4-Tetrahydroquinoxalines;407
1.10.1.1.3.1.2;16.15.5.3.1.2 Method 2: Aromatization by Oxidation of 1,2-Dihydroquinoxaline Derivatives;408
1.10.1.1.3.1.3;16.15.5.3.1.3 Method 3: Quinoxaline N-Oxides by N-Oxidation of Quinoxalines;409
1.10.1.1.3.1.4;16.15.5.3.1.4 Method 4: Quinoxaline 1,4-Dioxides by N-Oxidation of Quinoxalines;410
1.10.1.1.3.1.4.1;16.15.5.3.1.4.1 Variation 1: Quinoxaline 1,4-Dioxides by N-Oxidation of Quinoxaline N-Oxides;411
1.10.1.1.3.1.5;16.15.5.3.1.5 Method 5: Quinoxaline-2,3-diones from Quinoxalin-2-ones by Oxidation;412
1.10.1.1.3.2;16.15.5.3.2 Reductive Ring Modifications;412
1.10.1.1.3.2.1;16.15.5.3.2.1 Method 1: Reduction of Quinoxalines to 1,2,3,4-Tetrahydroquinoxalines;412
1.10.1.1.3.2.2;16.15.5.3.2.2 Method 2: Reduction of Quinoxalin-2-ones to 3,4-Dihydroquinoxalin-2(1H)-ones;414
1.10.1.1.3.2.3;16.15.5.3.2.3 Method 3: Reduction of Quinoxaline N-Oxides to Quinoxalines;414
1.10.1.1.3.2.4;16.15.5.3.2.4 Method 4: Reduction of Quinoxaline 1,4-Dioxides to Quinoxalines;415
1.10.1.1.3.3;16.15.5.3.3 Addition of C-Nucleophiles;416
1.10.1.1.3.3.1;16.15.5.3.3.1 Method 1: Addition of Ketone Enols to Quinoxalin-2-ones;416
1.10.1.1.3.3.2;16.15.5.3.3.2 Method 2: Addition of Anions Derived from 1-Haloalkyl Sulfones;416
1.10.1.1.3.3.3;16.15.5.3.3.3 Method 3: Addition of Organometallics;417
1.10.1.1.3.3.4;16.15.5.3.3.4 Method 4: Addition of Potassium Phenylacetylide to Quinoxaline 1-Oxides;418
1.10.1.1.3.3.5;16.15.5.3.3.5 Method 5: Cycloaddition Reactions;418
1.10.1.1.3.4;16.15.5.3.4 Elimination Reactions;419
1.10.1.1.3.4.1;16.15.5.3.4.1 Method 1: Aromatization by Elimination from 1-Acyl-1,2-dihydroquinoxalines;419
1.10.1.1.4;16.15.5.4 Ring Functionalization by Substitution of Ring Hydrogens or N-Alkylation;419
1.10.1.1.4.1;16.15.5.4.1 Method 1: Hydrogen–Deuterium Exchange;419
1.10.1.1.4.2;16.15.5.4.2 Method 2: Alkylation;420
1.10.1.1.4.2.1;16.15.5.4.2.1 Variation 1: Radical C-Alkylation;420
1.10.1.1.4.2.2;16.15.5.4.2.2 Variation 2: C-Alkylation of Quinoxaline Anions;420
1.10.1.1.4.2.3;16.15.5.4.2.3 Variation 3: N-Alkylation of Quinoxalin-2-ones;421
1.10.1.1.4.2.4;16.15.5.4.2.4 Variation 4: Synthesis of Onium Salts;422
1.10.1.1.4.3;16.15.5.4.3 Method 3: Acylation;423
1.10.1.1.4.3.1;16.15.5.4.3.1 Variation 1: Free-Radical Acylation of Quinoxaline;423
1.10.1.1.4.3.2;16.15.5.4.3.2 Variation 2: Electrophilic Acylation of Quinoxaline Anions;424
1.10.1.1.4.4;16.15.5.4.4 Method 4: Cyanation;424
1.10.1.1.4.5;16.15.5.4.5 Method 5: Halogenation;425
1.10.1.1.4.6;16.15.5.4.6 Method 6: Chlorosulfonylation;426
1.10.1.1.4.7;16.15.5.4.7 Method 7: Nitration;426
1.10.1.1.4.8;16.15.5.4.8 Method 8: Amination;427
1.10.1.1.5;16.15.5.5 Synthesis by Substituent Transformation;427
1.10.1.1.5.1;16.15.5.5.1 Transformation of Carbon Functionalities;427
1.10.1.1.5.1.1;16.15.5.5.1.1 Method 1: Substitution with Hydrogen;427
1.10.1.1.5.1.2;16.15.5.5.1.2 Method 2: Rearrangements of Carbon Functionalities;428
1.10.1.1.5.1.2.1;16.15.5.5.1.2.1 Variation 1: Curtius Rearrangement;428
1.10.1.1.5.1.2.2;16.15.5.5.1.2.2 Variation 2: Hofmann Rearrangement;428
1.10.1.1.5.1.3;16.15.5.5.1.3 Method 3: Oxidation;429
1.10.1.1.5.1.4;16.15.5.5.1.4 Method 4: Halogenation;430
1.10.1.1.5.1.5;16.15.5.5.1.5 Method 5: Reductive Amination of Quinoxaline-2-carbaldehyde;431
1.10.1.1.5.1.6;16.15.5.5.1.6 Method 6: Amidation of Quinoxaline Carboxylic Acids and Their Derivatives;431
1.10.1.1.5.1.7;16.15.5.5.1.7 Method 7: Reactions with Electrophiles;432
1.10.1.1.5.1.7.1;16.15.5.5.1.7.1 Variation 1: 3-Substitution of 3-Methylquinoxalin-2(1H)-one;432
1.10.1.1.5.1.7.2;16.15.5.5.1.7.2 Variation 2: Knoevenagel Reaction;433
1.10.1.1.5.2;16.15.5.5.2 Transformation of Halogen Functionalities;434
1.10.1.1.5.2.1;16.15.5.5.2.1 Method 1: Dehalogenation;434
1.10.1.1.5.2.2;16.15.5.5.2.2 Method 2: Halogen Exchange;435
1.10.1.1.5.2.3;16.15.5.5.2.3 Method 3: Halogen–Metal Exchange;435
1.10.1.1.5.2.4;16.15.5.5.2.4 Method 4: Reaction with C-Nucleophiles;436
1.10.1.1.5.2.4.1;16.15.5.5.2.4.1 Variation 1: Cyanation;436
1.10.1.1.5.2.4.2;16.15.5.5.2.4.2 Variation 2: a-Hetarylation of Esters, Lactones, Amides, and Nitriles with 2-Chloroquinoxaline;436
1.10.1.1.5.2.4.3;16.15.5.5.2.4.3 Variation 3: Cross Coupling with Organolithiums;437
1.10.1.1.5.2.4.4;16.15.5.5.2.4.4 Variation 4: Cross Coupling with Grignard Reagents;438
1.10.1.1.5.2.4.5;16.15.5.5.2.4.5 Variation 5: Cross Coupling with Organozinc Compounds;438
1.10.1.1.5.2.4.6;16.15.5.5.2.4.6 Variation 6: Stille Cross Coupling;439
1.10.1.1.5.2.4.7;16.15.5.5.2.4.7 Variation 7: Cross Coupling with Organoboron Compounds;439
1.10.1.1.5.2.4.8;16.15.5.5.2.4.8 Variation 8: Heck Cross Coupling;440
1.10.1.1.5.2.4.9;16.15.5.5.2.4.9 Variation 9: Sonogashira Cross Coupling;441
1.10.1.1.5.2.5;16.15.5.5.2.5 Method 5: Reaction with N-Nucleophiles;442
1.10.1.1.5.2.6;16.15.5.5.2.6 Method 6: Reaction with O-Nucleophiles;443
1.10.1.1.5.2.7;16.15.5.5.2.7 Method 7: Reaction with S-Nucleophiles;443
1.10.1.1.5.3;16.15.5.5.3 Transformation of Nitrogen Functionalities;444
1.10.1.1.5.3.1;16.15.5.5.3.1 Method 1: Reduction of Nitro Groups;444
1.10.1.1.5.3.2;16.15.5.5.3.2 Method 2: Substitution with a Halogen via Diazotization;444
1.10.1.1.5.3.3;16.15.5.5.3.3 Method 3: N-Alkylation;444
1.10.1.1.5.3.4;16.15.5.5.3.4 Method 4: N-Acylation;444
1.10.1.1.5.4;16.15.5.5.4 Transformation of Oxygen Functionalities;445
1.10.1.1.5.4.1;16.15.5.5.4.1 Method 1: Haloquinoxalines from the Corresponding Oxo Derivatives;445
1.10.1.1.5.4.2;16.15.5.5.4.2 Method 2: Reaction with C-Nucleophiles;446
1.10.1.1.5.4.3;16.15.5.5.4.3 Method 3: Reactions with N-Nucleophiles;447
1.10.1.1.5.4.4;16.15.5.5.4.4 Method 4: Reaction with S-Nucleophiles;447
1.10.1.1.5.4.5;16.15.5.5.4.5 Method 5: O-Alkylation;447
1.10.1.1.5.4.6;16.15.5.5.4.6 Method 6: O-Demethylation;448
1.10.1.1.5.5;16.15.5.5.5 Transformation of Sulfur Functionalities;448
1.10.1.1.5.5.1;16.15.5.5.5.1 Method 1: Oxidation;448
1.10.1.1.5.5.2;16.15.5.5.5.2 Method 2: Reaction with C-Nucleophiles;449
1.10.1.1.5.5.3;16.15.5.5.5.3 Method 3: Reaction with N-Nucleophiles;450
1.10.1.1.5.5.4;16.15.5.5.5.4 Method 4: S-Alkylation;450
1.10.1.1.5.5.5;16.15.5.5.5.5 Method 5: C--S Bond Cleavage;451
1.11;Volume 21: Three Carbon--Heteroatom Bonds: Amides and Derivatives; Peptides; Lactams;462
1.11.1;21.16 Synthesis of Scalemic Amides by Kinetic Resolution;462
1.11.1.1;21.16.1 Method 1: Kinetic Resolution by Acylation with Stoichiometric Amounts of Chiral Acylating Reagents;462
1.11.1.2;21.16.2 Method 2: Kinetic Resolution with Catalytic Amounts of a Chiral Promoter;467
1.11.1.2.1;21.16.2.1 Variation 1: Kinetic Resolution of Amines with Attenuated Reactivities;467
1.11.1.2.2;21.16.2.2 Variation 2: Kinetic Resolution with Azlactone-Derived Acylating Reagents;469
1.11.1.2.3;21.16.2.3 Variation 3: Kinetic Resolution with Carboxylic Acid Anhydrides as Acylating Reagents;471
1.11.1.2.4;21.16.2.4 Variation 4: Kinetic Resolution with a'-Hydroxyenones as Acylating Reagents;473
1.11.1.2.5;21.16.2.5 Variation 5: Kinetic Resolution with Carboxylic Acids as Acylating Reagents;476
1.12;Volume 27: Heteroatom Analogues of Aldehydes and Ketones;480
1.12.1;27.16 Product Class 16: Azines;480
1.12.1.1;27.16.3 Azines;480
1.12.1.1.1;27.16.3.1 Synthesis of Azines;480
1.12.1.1.1.1;27.16.3.1.1 1,4-Disubstituted Azines;480
1.12.1.1.1.1.1;27.16.3.1.1.1 Method 1: Reaction of Aldehydes with Hydrazine;480
1.12.1.1.1.1.2;27.16.3.1.1.2 Method 2: Reaction of Aldehyde Hydrazones with Aldehydes;481
1.12.1.1.1.1.3;27.16.3.1.1.3 Method 3: Hydrazone Oxidation;482
1.12.1.1.1.1.4;27.16.3.1.1.4 Method 4: Reaction of Aldehyde Hydrazones with Disulfur Compounds;483
1.12.1.1.1.1.5;27.16.3.1.1.5 Method 5: Reaction of Semicarbazones with Aldehydes;483
1.12.1.1.1.2;27.16.3.1.2 Trisubstituted Azines;484
1.12.1.1.1.2.1;27.16.3.1.2.1 Method 1: Reaction of Aldehyde Hydrazones with Ketones;484
1.12.1.1.1.2.2;27.16.3.1.2.2 Method 2: Reaction of Ketone Hydrazones with Aldehydes;484
1.12.1.1.1.3;27.16.3.1.3 Tetrasubstituted Azines;485
1.12.1.1.1.3.1;27.16.3.1.3.1 Method 1: Ketone Dimerization with Hydrazine;485
1.12.1.1.1.3.2;27.16.3.1.3.2 Method 2: Reaction of Hydrazones with Ketones;486
1.12.1.1.1.3.3;27.16.3.1.3.3 Method 3: Diazoalkane Dimerization;487
1.12.1.1.1.3.4;27.16.3.1.3.4 Method 4: Imine Oxidation;487
1.12.1.1.2;27.16.3.2 Applications of Azines in Organic Synthesis;488
1.12.1.1.2.1;27.16.3.2.1 Method 1: Oxidation and Reduction;488
1.12.1.1.2.2;27.16.3.2.2 Method 2: Addition Reactions;490
1.12.1.1.2.3;27.16.3.2.3 Method 3: Formation of Organometallic Complexes;491
1.12.1.1.2.4;27.16.3.2.4 Method 4: Intramolecular Cyclization Reactions;492
1.12.1.1.2.5;27.16.3.2.5 Method 5: Cycloaddition Reactions;493
1.12.1.1.2.6;27.16.3.2.6 Method 6: Hydrolytic Cleavage;494
1.12.1.1.2.7;27.16.3.2.7 Method 7: Ugi Reaction;495
1.12.2;27.17 Product Class 17: Hydrazones;500
1.12.2.1;27.17.5 Hydrazones;500
1.12.2.1.1;27.17.5.1 N-Unsubstituted Hydrazones;500
1.12.2.1.1.1;27.17.5.1.1 Synthesis of N-Unsubstituted Hydrazones;500
1.12.2.1.1.1.1;27.17.5.1.1.1 Method 1: Synthesis from Aldehydes and Ketones;500
1.12.2.1.1.1.1.1;27.17.5.1.1.1.1 Variation 1: From Oximes;500
1.12.2.1.1.1.2;27.17.5.1.1.2 Method 2: Synthesis from Diazo Compounds;501
1.12.2.1.1.1.3;27.17.5.1.1.3 Method 3: Synthesis from Unsaturated Hydrocarbons;503
1.12.2.1.1.1.3.1;27.17.5.1.1.3.1 Variation 1: From Terminal Alkynes;503
1.12.2.1.1.1.3.2;27.17.5.1.1.3.2 Variation 2: From Allenes;504
1.12.2.1.1.1.3.3;27.17.5.1.1.3.3 Variation 3: From Fluoroalkenes;504
1.12.2.1.1.2;27.17.5.1.2 Applications of N-Unsubstituted Hydrazones in Organic Synthesis;505
1.12.2.1.1.2.1;27.17.5.1.2.1 Method 1: Reductive Elimination of the Hydrazono Group;505
1.12.2.1.1.2.2;27.17.5.1.2.2 Method 2: Synthesis of Nitrogen Heterocycles;506
1.12.2.1.1.2.3;27.17.5.1.2.3 Method 3: Synthesis of Diazo Compounds by Oxidation;507
1.12.2.1.1.2.4;27.17.5.1.2.4 Method 4: Synthesis of Halogenated Alkenes;509
1.12.2.1.2;27.17.5.2 N-Monosubstituted Hydrazones;511
1.12.2.1.2.1;27.17.5.2.1 Synthesis of N-Monosubstituted Hydrazones;511
1.12.2.1.2.1.1;27.17.5.2.1.1 Method 1: Synthesis from Aldehydes and Ketones;511
1.12.2.1.2.1.1.1;27.17.5.2.1.1.1 Variation 1: Hydroformylation–Hydrazone Formation from Alkenes;512
1.12.2.1.2.1.1.2;27.17.5.2.1.1.2 Variation 2: Synthesis from Masked Carbonyl Groups;513
1.12.2.1.2.1.2;27.17.5.2.1.2 Method 2: Synthesis by Arylation of Benzophenone Hydrazone;513
1.12.2.1.2.1.3;27.17.5.2.1.3 Method 3: Synthesis from Activated Methylene Compounds;514
1.12.2.1.2.1.3.1;27.17.5.2.1.3.1 Variation 1: Reaction with Benzotriazoles;514
1.12.2.1.2.1.3.2;27.17.5.2.1.3.2 Variation 2: Reaction with Diazonium Salts;514
1.12.2.1.2.1.4;27.17.5.2.1.4 Method 4: Synthesis from Terminal Alkynes;515
1.12.2.1.2.1.5;27.17.5.2.1.5 Method 5: Synthesis from Diazo Esters;516
1.12.2.1.2.2;27.17.5.2.2 Applications of N-Monosubstituted Hydrazones in Organic Synthesis;516
1.12.2.1.2.2.1;27.17.5.2.2.1 Method 1: Synthesis of Nitrogen Heterocycles;517
1.12.2.1.2.2.1.1;27.17.5.2.2.1.1 Variation 1: Fischer Indole Synthesis from N-Arylhydrazones;517
1.12.2.1.2.2.2;27.17.5.2.2.2 Method 2: N-tert-Butylhydrazones as Acyl Anion Equivalents;517
1.12.2.1.2.2.3;27.17.5.2.2.3 Method 3: Synthesis of N,N-Disubstituted Hydrazones by Acylation;518
1.12.2.1.2.2.4;27.17.5.2.2.4 Method 4: Synthesis of Bicyclic Diazenium Salts;518
1.12.2.1.3;27.17.5.3 N,N-Disubstituted Hydrazones;519
1.12.2.1.3.1;27.17.5.3.1 Synthesis of N,N-Disubstituted Hydrazones;519
1.12.2.1.3.1.1;27.17.5.3.1.1 Method 1: Synthesis from Aldehydes and Ketones;519
1.12.2.1.3.1.1.1;27.17.5.3.1.1.1 Variation 1: Synthesis from Masked Aldehydes and Ketones;520
1.12.2.1.3.1.1.2;27.17.5.3.1.1.2 Variation 2: Solid-Supported Synthesis;520
1.12.2.1.3.1.2;27.17.5.3.1.2 Method 2: Synthesis from Unsaturated Hydrocarbons;522
1.12.2.1.3.1.3;27.17.5.3.1.3 Method 3: Synthesis from N-Monosubstituted Hydrazones;523
1.12.2.1.3.2;27.17.5.3.2 Applications of N,N-Disubstituted Hydrazones in Organic Synthesis;523
1.12.2.1.3.2.1;27.17.5.3.2.1 Method 1: Alkylation of Hydrazone Anions;523
1.12.2.1.3.2.1.1;27.17.5.3.2.1.1 Variation 1: Solid-Supported Synthesis;524
1.12.2.1.3.2.1.2;27.17.5.3.2.1.2 Variation 2: Alkylation of Cyclic Carbamates Derived from N-Acyl-N-alkylhydrazones;526
1.12.2.1.3.2.2;27.17.5.3.2.2 Method 2: Primary Amine Synthesis;527
1.12.2.1.3.2.2.1;27.17.5.3.2.2.1 Variation 1: Solid-Supported Synthesis;528
1.12.2.1.3.2.3;27.17.5.3.2.3 Method 3: Radical Reactions;529
1.12.2.1.3.2.3.1;27.17.5.3.2.3.1 Variation 1: Radical Cyclization;529
1.12.2.1.3.2.3.2;27.17.5.3.2.3.2 Variation 2: Radical Addition;530
1.12.2.1.3.2.4;27.17.5.3.2.4 Method 4: Cycloaddition Reactions;531
1.12.2.1.3.2.4.1;27.17.5.3.2.4.1 Variation 1: [4 + 2]-Cycloaddition Reactions;531
1.12.2.1.3.2.4.2;27.17.5.3.2.4.2 Variation 2: [2 + 2]-Cycloaddition Reactions;531
1.12.2.1.3.2.5;27.17.5.3.2.5 Method 5: Cleavage of N,N-Dialkylhydrazones;532
1.12.2.1.3.2.5.1;27.17.5.3.2.5.1 Variation 1: Solid-Phase Synthesis of Nitriles;533
1.12.2.1.4;27.17.5.4 N-Sulfonylated Hydrazones;533
1.12.2.1.4.1;27.17.5.4.1 Synthesis of N-Sulfonylated Hydrazones;533
1.12.2.1.4.1.1;27.17.5.4.1.1 Method 1: Synthesis from Aldehydes and Ketones;533
1.12.2.1.4.1.1.1;27.17.5.4.1.1.1 Variation 1: Synthesis from O,O-Acetals;535
1.12.2.1.4.1.2;27.17.5.4.1.2 Method 2: Synthesis from Nitriles;535
1.12.2.1.4.1.3;27.17.5.4.1.3 Method 3: N-Alkylation of N-Tosylhydrazones;536
1.12.2.1.4.2;27.17.5.4.2 Applications of N-Sulfonylated Hydrazones in Organic Synthesis;537
1.12.2.1.4.2.1;27.17.5.4.2.1 Method 1: Synthesis of Unsaturated Hydrocarbons;537
1.12.2.1.4.2.1.1;27.17.5.4.2.1.1 Variation 1: Synthesis of Alkenes;537
1.12.2.1.4.2.1.2;27.17.5.4.2.1.2 Variation 2: Synthesis of Allenes;541
1.12.2.1.4.2.1.3;27.17.5.4.2.1.3 Variation 3: Synthesis of Alkynes;542
1.12.2.1.4.2.2;27.17.5.4.2.2 Method 2: N-Sulfonylated Hydrazones in Reduction Reactions;543
1.12.2.1.4.2.2.1;27.17.5.4.2.2.1 Variation 1: Synthesis of Sulfides and Ethers;544
1.12.2.1.4.2.2.2;27.17.5.4.2.2.2 Variation 2: Synthesis of Sulfones;545
1.12.2.1.4.2.2.3;27.17.5.4.2.2.3 Variation 3: Synthesis of Arenes from Arylboronic Acids;546
1.12.2.1.4.2.3;27.17.5.4.2.3 Method 3: Synthesis of a-Alkylated and a,a-Dialkylated N-Tosylhydrazones;547
1.12.2.1.4.2.4;27.17.5.4.2.4 Method 4: Synthesis of Nitrogen Heterocycles;548
1.12.3;27.18 Product Class 18: Hydrazonium Compounds;556
1.12.3.1;27.18.3 Hydrazonium Compounds;556
1.12.3.1.1;27.18.3.1 1,1,1-Trialkyl-2-alkylidenehydrazinium Compounds;556
1.12.3.1.1.1;27.18.3.1.1 Synthesis of 1,1,1-Trialkyl-2-alkylidenehydrazinium Compounds;556
1.12.3.1.1.1.1;27.18.3.1.1.1 Method 1: Alkylation of Hydrazone Compounds;556
1.12.3.1.1.2;27.18.3.1.2 Applications of 1,1,1-Trialkyl-2-alkylidenehydrazinium Compounds in Organic Synthesis;557
1.12.3.1.1.2.1;27.18.3.1.2.1 Method 1: Synthesis of Azirines;557
1.12.3.1.1.2.2;27.18.3.1.2.2 Method 2: Synthesis of Pyrroles;558
1.12.3.1.1.2.3;27.18.3.1.2.3 Method 3: Synthesis of Ketones;558
1.13;Author Index;560
1.14;Abbreviations;590
1.15;List of All Volumes;596

Leseproben

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–?5-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–?5-Dienyl Complexes
1.4.5.1.1 Synthesis of Cobalt–?5-Dienyl Complexes
1.4.5.1.1.1 Method 1: Synthesis of Chiral Dicarbonyl(?5-cyclopentadienyl)cobalt(I) and (?5-Cyclopentadienyl)(?4-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–?5-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(?5-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(?5-cyclopentadienyl)cobalt(I) Complex from Octacarbonyldicobalt(0) and a Chiral Cyclopentadiene[11] Dicarbonyl{?5-(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; [a]D26 +70 (c 0.00095, 95% EtOH). 1.4.5.1.1.1.2 Variation 2: Synthesis of Chiral (?5-Cyclopentadienyl)(?4-diene)cobalt(I) Complexes by Substitution of Ligands Several chiral (?5-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 (?5-Cyclopentadienyl)(?4-diene)cobalt(I) Complexes[12,13] (+)-(?4-Cycloocta-1,5-diene)(?5-1-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; [a]D20 +156 (c 0.06, toluene). (?4-Cycloocta-1,5-diene){?5-(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; [a]D20 +5.5 (c 0.17, toluene). 1.4.5.1.1.2 Method 2: Synthesis of (Alkene)carbonyl(?5-cyclopentadienyl)cobalt(I) Complexes via Displacement of One Carbonyl Moiety Among the commercially available cyclopentadienylcobalt catalysts, dicarbonyl(?5-cyclopentadienyl)cobalt(I) is probably the most widely used. Its activation usually requires heat and/or visible light. The use of (?4-cycloocta-1,5-diene)(?5-cyclopentadienyl)cobalt(I), which has been employed mostly for the preparation of pyridines, also requires high temperatures and/or light. Conversely, (?5-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(?5-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...