Ready access to a branched Man5 oligosaccharide based on regioselective glycosylations of a mannose-tetraol with n-pentenyl orthoesters

Abstract

A branched Man₅ oligosaccharide has been synthesized by sequential regioselective glycosylations on a mannose-tetraol with n-pentenyl orthoester glycosyl-donors promoted by NIS/BF₃·Et₂O, in CH₂Cl₂. An extended n-pentenyl chain was incorporated into the tetraol acceptor to facilitate (a) the solubility of the starting tetraol in CH₂Cl₂, and (b) future manipulations at the reducing end of the Man₅ oligosaccharide.