Stereodirected Synthesis with Organoboranes - Matteson, Donald S.
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This chapter provides abrief overview of organoborane reaction types. Reaction mechanisms are discussed, particularly with reference to whether they may or may not allow stereocontrol, but stereocontrolled applications are deferred to later chap ters. Reactions that replace boron by atoms other than carbon are discussed first (Section 3. 2), followed by boron substituted carbanions (Section 3. 3) and reactions that have the net effect of replacing boron-carbon bonds by carbon-carbon bonds (Section 3. 4). However, ß-eliminations, which also create a carbon-carbon bond at the expense of a…mehr

Produktbeschreibung
This chapter provides abrief overview of organoborane reaction types. Reaction mechanisms are discussed, particularly with reference to whether they may or may not allow stereocontrol, but stereocontrolled applications are deferred to later chap ters. Reactions that replace boron by atoms other than carbon are discussed first (Section 3. 2), followed by boron substituted carbanions (Section 3. 3) and reactions that have the net effect of replacing boron-carbon bonds by carbon-carbon bonds (Section 3. 4). However, ß-eliminations, which also create a carbon-carbon bond at the expense of a boron-carbon bond, are deferred to Section 4. 2. Finally, a variety of reactions of organoboranes that leave the boron-carbon bond intact and affect other functionality are described in Section 3. 5. 3. 2 Oxidative Replacement of Boron 3. 2. 1 Introduction Several oxidative boron-carbon bond cleavage reactions replace the boron atom stereospecifically with retention of configuration of the carbon atom, and therefore are particularly useful in asymmetric synthesis. These share the following general mechanistic features: (I) Coordination of an oxidizing agent having a nucleophilic site, (:Y_Z)-n (n = 0 or I), to the boron to form aborate complex (1). (2) Intramolecular migration of carbon from the electron-rich boron atom to the rela tively electron-deficient atom Y with concurrent displacement of nucleofuge z-n, as illustrated by transition state 2 and product 3.
  • Produktdetails
  • Reactivity and Structure: Concepts in Organic Chemistry .32
  • Verlag: Springer, Berlin
  • Softcover reprint of the original 1st ed. 1995
  • Seitenzahl: 420
  • Erscheinungstermin: 29. Dezember 2011
  • Englisch
  • Abmessung: 235mm x 155mm x 22mm
  • Gewicht: 633g
  • ISBN-13: 9783642797118
  • ISBN-10: 3642797113
  • Artikelnr.: 36119350
Inhaltsangabe
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.-
Rezensionen
"...this is the type of book that could only be written by a scholar who has devoted many years to organoboron chemistry. Matteson has done it, and done it well." - Synthesis