Jean-Gabriel Gourcy

Utilisation des methodes biologiques pour la preparation de synthons chiraux : I-reduction de β-dicetones acycliques par saccharomyces cerevisiae (levure de boulanger)

Abstract The reduction of acyclic β-dikotenes by bakers yeast gave ketols, in many cases with high optical purity. The reaction is easy to carry out and provides chiral molecules of high synthetic interest.

Enantiomeric excess analysis of (2R, 3S)-3-deuterio-2-methylcyclohexanone and (1S, 2R, 3S)-3-deuterio-2-methylcyclohexanol, through deuterium NMR in a polypeptide lyotropic liquid crystal

Abstract Poly-γ-benzyl-L-glutamate (PBLG) and dichloromethane form a lyotropic liquid crystal which can be used as solvent for enantiomeric excess analysis of molecules containing several stereogenic centers, through deuterium NMR spectroscopy. All isomers of 3-deuterio-2-methylcyclohexanone and of 3-deuterio-2-methylcyclohexanol dissolved in PBLG/CH 2 Cl 2 solvents, exhibit different quadrupolar splittings on their deuterium NMR spectra, which allows an accurate determination of their diastereoisomeric and enantiomeric excesses.

2- and 8-Functionalized 1,4,7,10-tetraoxaspiro [5.5] undecanes. Part 4. Conformational study by 1H and 13C NMR spectroscopy

1 H and 13C NMR spectra of new 1,4,7,10-tetraoxygenated spiroacetals 1, 2, 3 and 4, were analysed by using 1D and 2D methods. This allowed us to give a definite structural characterization of the E,E, Z,E and E,Z isomers obtained by a cyclodehydrative reaction carried out on a dihydroxyketone precursor, under thermodynamic control. The introduction of oxygen atoms in the 4 and 10 positions did not modify the structural features previously observed for 1,7-dioxygenated spiroacetals obtained from natural and synthetic sources.

Chain contraction in anodic oxidation of gem-polysulphides

Anodic oxidation of some aromatic gem-polysulphides results, unexpectedly, in chain contraction giving in dry solvents an α-disulphide or, in wet solvents, a thiosulphonate.

ELEKTROREDUKTION VON SULFONYLHALOGENIDEN IN ORGANISCHEN LOESUNGSMITTELN, ANWENDUNG ZUR DIREKTEN SYNTHESE VON SULFONEN UND SULFIDEN

Die kathodische Reduktion von Sulfonylchloriden der Zusammensetzung Ar-SO2Cl (Ar: Phenyl, p-Methyl-, p-Methoxy- und p-Brom-phenyl) in Acetonitril fuhrt in Gegenwart eines Elektrophilen zu Sulfonen (Ar-SO2-CH3) und Sulfiden (Ar-S-CH3), in Gegenwart von Perchlorsaure je nach der Elektrolysedauer zu Thiosulfonaten (Ar-SO2-S-Ar), Disulfiden (Ar-S-S-Ar) oder Thiolen (Ar-SH).