A. Hercouet

Acyloxyalkylidènephosphoranes—III : Etude des ω-acyloxybenzylidènetriphénylphosphoranes.nouvelle voie d'accès aux benzofurannes1

Abstract The intramolecular condensation of o-acyloxybenzylidenetriphenylphosphoranes leads to acylated products in t-BuOH and to benzofurans in toluene. Mechanistic aspects are discussed. A general method is described for the synthesis of benzofurans from o-cresols, o-hydroxybenzylic alcohols, and deactivated phenols.

Une nouvelle voie d'accès aux benzofurannes

Abstract The reaction of acid chloride or acid anhydride with o-hydroxybenzyl triphenylphosphonium bromide, in presence of triethylamine, gives benzofurannes.

Belokon's Ni(II) complex as a chiral masked glycine for the diastereoselective synthesis of 2-substituted 1-aminocyclopropane carboxylic acids☆

Abstract (1S,2R)- and (1R,2S)-Allonorcoronamic acids have been efficiently synthesised from the cyclic sulfate of 1,2-propanediol and Belokons complex (a complex of Ni(II) with glycine-(S)-2-[N′-(N-benzylprolyl)amino]benzophenone Schiff base ligands). The stereochemical outcome of the reaction was totally controlled by the sulfate partner.

Expedient synthesis of (−)-(1S, 2R)-Allonorcoronamic acid

Abstract The title amino acid was synthesized in enantiomerically pure form, starting from ( S )-(+)-1,2-propanediol 2 in three steps, by condensation of cyclic sulfate 3 with methyl benzylideneglycinate.

Asymmetric synthesis of a phosphonic analogue of (−)-allo-norcoronamic acid

Abstract (−)-(1R,2R)-1-Amino-2-methylcyclopropanephosphonic acid was synthesized in an enantiomerically pure form starting from the cyclic sulfate of (+)-(S)-1,2-propanediol and dimethyl t-butoxycarbonylmethylphosphonate.

First asymmetric synthesis of (−)-(2S, 3R)-methanoproline

Abstract The title amino acid was synthesized in enantiomerically pure form, starting from ( S )-(−)-butanetriol 1 , by condensation of cyclic sulfate 3 with methyl benzylideneglycinate.

Boron- and Silicon-Substituted [3]-1-Heterodendralenes as Versatile Building Blocks for the Rapid Construction of Polycyclic Architectures

B and Si, additional assets: Skeletally diverse polycyclic compounds with up to six stereocenters were assembled with excellent stereoselectivity from simple 2-vinyl α,β-unsaturated aldehydes possessing a trimethylsilyl or a boronate group at position 3 (see scheme). The pre-encoded skeletal information was ensured by the initial choice of the positions of the heteroatoms (O, Si or B).

Synthesis of optically active 2,3-methanopipecolic acid

Abstract The title compound was synthesized in enantiomerically pure form, starting from L -glutamic acid.

Effect of the Temperature on the Stoichiometry of Borane Dimethyl Sulfide Reduction of Secondary and Tertiary Amides

Abstract A simple procedure has been described for the reduction of secondary and tertiary amides to amines using borane-dimethyl sulfide in theoretical amounts.

Acyloxyalkylidènephosphoranes—I : Etude des ω-acyloxy n-propylidènetriphénylphosphoranes. synthése de dihydro-2,3 furannes

Abstract The ω-acyloxy n-propylidenephosphoranes give 2,3-dihydrofurans in toluene, and cyclopropylcetones in t-butanol. The mechanism of these reactions was investigated; formation of cyclopropylketone does not result from intramolecular condensation but from two intermolecular condensations.