Chemical and enzymatic diastereoselective cleavage of β-d-galactopyranosylsulfoxides

Abstract The self induced diastereoselective oxidation of several thio-β- d -galactopyranosides to the corresponding sulfoxides, has been shown to occur in high yield. Up to 74% diastereomeric excess could be obtained depending on the structure and the conformation of the starting thioglycoside. R s and S s Phenylsulfinyl-β- d -galactopyranosides have been obtained in optically pure forms, their chemical as well as enzymatic hydrolysis with triflic acid and with β-galactosidase have been shown to proceed diastereoselectively, the structure of the sulfoxide 4′ S with the S onfiguration at the sulfinyl sulfur has been determined by X-ray analysis.