Regioselective oxidative cleavage of benzylidene acetals of glycopyranosides with periodic acid catalyzed by tetrabutylammonium bromide

Abstract

A combination of periodic acid, tetrabutylammonium bromide, and wet alumina in dichloromethane efficiently oxidized benzylidene acetals of carbohydrates to the corresponding hydroxybenzoates in excellent yields (>90%). Under these conditions, other protecting groups, such as tert-butyl(dimethyl)silyl, tert-butyl(diphenyl)silyl, and functional groups, such as epoxide, were unaffected. By varying the nature of the protecting group at the C3 position, good to high regioselectivity toward 4- or 6-benzoates was obtained. © Georg Thieme Verlag Stuttgart · New York.