This monograph has been written to demonstrate to organic chemists and graduate students the strategies for controlling sterochemistry in carbon-carbon bond formations with borane intermediates. The boranes were initially found to be useful reagents by Nobel Laureate H.C. Brown. Their precursors are commercially available and derivatization is fast, clean and simple.

Inhalt

1 Introduction to Borane Chemistry.- 1.1 Beginnings.- 1.2 Structure and Bonding in Organoboranes.- 1.2.1 General Characteristics of Boranes.- 1.2.2 Size.- 1.2.3 Bond Strengths.- 1.3 General Chemical Properties of Organoboranes.- 1.3.1 Oxidation States of Boron.- 1.3.2 Ligand Exchange on Boron.- 1.3.3 Acidities.- 1.4 Safety Considerations.- 1.4.1 General Hazards.- 1.4.2 Laboratory Handling.- 1.5 References.- 2 Sources of Compounds Containing Boron-Carbon Bonds.- 2.1 Industrial Sources of Boron Compounds.- 2.2 The Organometallic Route.- 2.2.1 Boronic Esters.- 2.2.1.1 Grignard and Lithium Reagents.- 2.2.1.2 Other Organometallics.- 2.2.2 Di-, Tri-, and Tetraborylmethanes.- 2.2.3 Borinic Esters (Dialkylalkoxyboranes).- 2.2.4 Trialkylboranes.- 2.3 Hydroboration.- 2.3.1 General Considerations.- 2.3.2 Mechanism of Hydroboration.- 2.3.3 Hydroborating Agents.- 2.3.3.1 Borane Sources.- 2.3.3.2 Alkylborane reagents.- 2.3.3.3 Oxygen substituted hydroborating agents.- 2.3.3.4 Haloboranes.- 2.3.4 Catalyzed Hydroborations.- 2.4 Haloborations.- 2.5 Other Routes to Carbon-Boron Bonds.- 2.6 References.- 3 General Reactions of Organoboranes.- 3.1 Introduction.- 3.2 Oxidative Replacement of Boron.- 3.2.1 Introduction.- 3.2.2 Oxygen Electrophiles.- 3.2.2.1 Hydrogen peroxide.- 3.2.2.2 Migratory aptitudes.- 3.2.2.3 Sodium perborate and other peroxides.- 3.2.2.4 Trimethylamine N-oxide.- 3.2.2.5 Molecular oxygen.- 3.2.2.6 Other reagents.- 3.2.3 Nitrogen Electrophiles.- 3.2.3.1 Chloramine and hydroxylaminesulfonic acid.- 3.2.3.2 Alkyl azides.- 3.2.3.3 Rearrangement of a-aminoboranes.- 3.2.4 Halogenation.- 3.2.4.1 Stereoselective replacements.- 3.2.4.2 Halogenation at carbon adjacent to boron.- 3.2.5 Sulfur.- 3.2.6 Protonolysis.- 3.2.7 Metalation.- 3.3 Boron Substituted Carbanions.- 3.3.1 By Deboronation.- 3.3.2 By Destannylation.- 3.3.3 By Deprotonation.- 3.3.4 By Michael Addition.- 3.4 Replacement of Boron by Carbon.- 3.4.1 Introduction.- 3.4.2 ?-Eliminations as Nuisance Reactions.- 3.4.3 Migrations to Electron-Deficient ?-Carbon.- 3.4.3.1 Introduction.- 3.4.3.2 Discovery of process and mechanism.- 3.4.3.3 Favored reaction pathways.- 3.4.3.4 Routes to ?-haloalkylboron compounds.- 3.4.3.5 The stereocontrollable route to halo boronic esters.- 3.4.3.6 Alkylation of (halomethyl)boronic esters.- 3.4.3.7 Simple homologation of boronic and borinic esters.- 3.4.3.8 Rearrangement of a,b-unsaturated borates.- 3.4.3.9 Carbonylation and cyanidation.- 3.4.3.10 Other chain extensions.- 3.4.4 Displacement of Boron by Electrophilic Carbon.- 3.4.4.1 Polar displacements.- 3.4.4.2 Small ring formation.- 3.4.4.3 Radical displacement mechanisms.- 3.4.5 Allylborane Chemistry.- 3.4.5.1 Introduction.- 3.4.5.2 Triallylborane.- 3.4.5.3 Intramolecular allylic rearrangements.- 3.4.5.4 Allylic bisboranes.- 3.4.5.5 Three-carbon chain extension of boronic esters.- 3.4.5.6 3-Borolenes.- 3.4.5.7 Allenyl and propargyl boranes.- 3.4.6 Photochemical Rearrangements.- 3.5 Reactions at Sites Other than the B-C Bond.- 3.5.1 Introduction.- 3.5.2 Nucleophilic Reactions of a-Halo Boronic Esters.- 3.5.2.1 Displacements.- 3.5.2.2 Eliminations.- 3.5.3 ?-Bromination.- 3.5.4 Oxidations of Other Functions in the Presence of C-B Bonds.- 3.5.5 Additions to Double Bonds.- 3.5.5.1 Radical additions.- 3.5.5.2 Polar and catalytic additions.- 3.5.5.3 Cycloadditions.- 3.5.5.4 Cyclopropanation.- 3.6 References.- 4 Alkenylboranes and Control of Olefinic Geometry.- 4.1 Introduction.- 4.2 ?-Elimination Routes to Unsaturated Compounds.- 4.2.1 Simple Alkenes.- 4.2.1.1 Introduction.- 4.2.1.2 Stereochemistry.- 4.2.1.3 Fragmentation.- 4.2.1.4 Alkenes from enamines.- 4.2.2 Routes to Alkenylboranes.- 4.2.2.1 (E)-1 - Alkenylboranes from 1 -alkynes.- 4.2.2.2 Alkenylboranes from disubstituted alkynes.- 4.2.3 Inversion of (E)- to (Z)-Alkenylboranes.- 4.2.4 Other Routes to Alkenylboranes.- 4.2.5 The Zweifel Olefin Synthesis.- 4.3 The Suzuki Coupling Reaction.- 4.3.1 Scope of the Reaction.- 4.3.2 Synthetic Applications.- 4.4 Other Stereoselective Routes to Alkenes.- 4.4.1 Alkenylpropargylic and Alkenylallenic Boranes.- 4.4.2 Insertion into Carbon-Boron Bonds.- 4.4.3 ?,?-Unsaturated Ketones from Boron Enolates.- 4.5 References.- 5 Asymmetric Synthesis via (a-Haloalkyl)boronic Esters.- 5.1 Introduction.- 5.1.1 Overview.- 5.1.2 Nomenclature Notes.- 5.1.2.1 Chirality descriptors.- 5.1.2.2 Bond illustration conventions.- 5.1.2.3 Drawings of bicyclic structures.- 5.2 Synthetic Methodology: Pinanediol Esters.- 5.2.1 Original Process.- 5.2.1.1 Preparation of pinanediol.- 5.2.1.2 Discovery of pinanediol boronic ester chemistry.- 5.2.1.3 Epimerization of (a-chloroalkyl)boronic esters.- 5.2.2 Zinc Chloride Promotion of a-Halo Boronic Ester Formation.- 5.2.3 Functional Group Compatibility.- 5.2.3.1 Alkoxy substituents.- 5.2.3.2 An azido substituent.- 5.2.3.3 Thioether substituents.- 5.2.3.4 Halogen substituents.- 5.2.3.5 Carboxylic ester substituents.- 5.2.3.6 Unsaturated boronic esters.- 5.2.4 Quaternary Chiral Centers.- 5.2.5 Pinanediol Recovery.- 5.2.6 Nonequivalent Faces of Boron in Pinanediol Esters.- 5.3 Synthetic Methodology: Chiral Directors Having C2 Symmetry.- 5.3.1 Butanediol Esters.- 5.3.1.1 Synthetic routes made possible by C2 symmetry.- 5.3.1.2 Nomenclature of cyclic boronic esters.- 5.3.2 Diisopropylethanediol (DIPED) Esters.- 5.3.2.1 Introduction.- 5.3.2.2 Synthesis of DIPED.- 5.3.3 Dicyclohexylethanediol (DICHED) Esters.- 5.3.3.1 Introduction.- 5.3.3.2 Synthesis of DICHED.- 5.3.4 Ultrahigh Stereoselectivity with C2 Symmetry.- 5.3.4.1 Introduction.- 5.3.4.2 Background.- 5.3.4.3 Discovery of enhanced selectivity.- 5.3.4.4 Kinetic resolution.- 5.3.4.5 Mechanistic interpretation.- 5.3.5 Convergent Connection of Two Asymmetric Centers.- 5.3.6 Reaction of Enolates.- 5.3.7 Allylic Boronic Esters.- 5.3.7.1 (?-Haloallyl)boronic esters.- 5.3.7.2 Asymmetric synthesis of an allylic boronic ester.- 5.3.7.3 Chain extension of allylboronic esters.- 5.4 Synthetic Applications.- 5.4.1 A Useful Mnemonic for Chiral Direction.- 5.4.2 Amido Boronic Esters.- 5.4.3 Insect Pheromones.- 5.4.3.1 Introduction.- 5.4.3.2 exo-Brevicomin.- 5.4.3.3 Eldanolide.- 5.4.3.4 (3S,4S)- and (3R,4S)-4-Methyl-3-heptanol.- 5.4.3.5 Stegobiol and stegobinone.- 5.4.4 Polyols.- 5.4.4.1 L-Ribose.- 5.4.4.2 Asymmetrically deuterated glycerol.- 5.4.5 Amino Acids.- 5.5 References.- 6 Asymmetric Hydroboration Chemistry.- 6.1 Introduction.- 6.2 Asymmetric Hydroboration.- 6.2.1 Reagents.- 6.2.1.1 Purification of pinylboranes.- 6.2.1.2 Recovery of ?-pinene.- 6.2.1.3 Alternative chiral directors.- 6.2.2 Hydroboration with Diisopinocampheylborane.- 6.2.3 Hydroboration with Monoisopinocampheylborane.- 6.3 Transformations of Asymmetric Organoboranes.- 6.3.1 Overview.- 6.3.1.1 General summary of transformations.- 6.3.1.2 Interconversions of boron oxidation states.- 6.3.2 Carbon-Carbon Bond Formation.- 6.3.2.1 Introduction.- 6.3.2.2 Methylene insertion routes.- 6.3.2.3 Borinic ester intermediates.- 6.3.2.4 Enolate insertions.- 6.3.2.5 Thexylborane and pinylborane intermediates.- 6.3.3 Carbon-Nitrogen Bond Formation.- 6.4 Substrate Directed Hydroboration.- 6.4.1 Noncatalytic methods.- 6.4.1.1 Introduction.- 6.4.1.2 Isopropenyl group hydroboration.- 6.4.1.3 Cyclic borane intermediates.- 6.5 Catalytic Asymmetric Hydroboration.- 6.5.1 Catalyst Effects in Substrate Directed Hydroboration.- 6.5.2 Hydroboration with Asymmetric Catalysts.- 6.6 References.- 7 Allylboron and Boron Enolate Chemistry.- 7.1 Introduction.- 7.2 Allylic Boronic Esters.- 7.2.1 General Advantages.- 7.2.2 Sources of Allylic Boronic Esters.- 7.2.2.1 Ally…