Useful approach to the synthesis of aryl thio- and selenoglycosides in the presence of rongalite

A simple, mild, and cost effective methodology has been developed for the synthesis of aryl thio-and selenoglycosides from glycosyl halides and diaryl dichalcogenides. Diaryl dichalcogenides undergo reductive cleavage in the presence of rongalite (HOCH2SO2Na) to generate a chalcogenide anion in situ followed by reaction with glycosyl halides to furnish the corresponding aryl thio- and selenoglycosides in excellent yields. Using this protocol, synthesis of 4-methyl-7-thioumbelliferyl-β-d-cellobioside (MUS-CB), a fluorescent non-hydrolyzable substrate analogue for cellulases has been achieved.