HIGHLY DIASTEREOSELECTIVE METHYLENE TRANSFER FROM DIAZOMETHANE TO THECARBONYL OF BETA-KETO SULFOXIDES - A GENERAL-APPROACH TO SYNTHETICALLY VERSATILE FLUORINE-CONTAINING CHIRAL BUILDING-BLOCKS

This paper describes the reactions of diazomethane with alpha-alkyl an d alpha-phenyl-substituted (R-S)-beta-keto sulfoxides bearing difluoro -, trifluoro- and difluorochloromethyl groups on the terminal site, to afford the corresponding diastereo- and enantiomerically pure epoxide s. A plausible mechanistic rationale for the origin of the stereochemi cal preferences in these reactions has been provided. Synthetic versat ility of the resultant epoxides has been demonstrated by a series of k ey transformations of the epoxide ring and the sulfinyl group includin g ring-opening, reductive desulfurization and syn-elimination reaction s. (C) 1998 Elsevier Science Ltd. All rights reserved.