CHEMICAL AND ENZYMATIC DIASTEREOSELECTIVE CLEAVAGE OF BETA-D-GALACTOPYRANOSYLSULFOXIDES

The self induced diastereoselective oxidation of several thio-beta D-g alactopyranosides to the corresponding sulfoxides, has been shown to o ccur in high yield. Up to 74% diastereomeric excess could be obtained depending on the structure and the conformation of the starting thiogl ycoside.Rs and Ss Phenylsulfinyl-beta-D-galactopyranosides have been o btained in optically pure forms, their chemical as well as enzymatic h ydrolysis with triflic acid and with beta-galactosidase have been show n to proceed diastereoselectively, the structure of the sulfoxide 4'S with the S configuration at the sulfinyl sulfur has been determined by X-ray analysis. (C) 1997 Elsevier Science Ltd.