Much attention has been focused on the stereoselective synthesis of glycosides and oligosaccharides, not only for the preparation of natural products,1but also for the homologation of sugars to serve as chiral templates for more complex synthetic targets.2Most current methods for the preparation of glycosides are based on the activation of a leaving group at the anomeric centre.3A wide range of (potential) leaving groups has been proposed. Some of them are stable in the absence of a suitable promoter and function as a temporary protecting group; others are very reactive.3The trifluoroacetoxyl group was found to be a good leaving group at the anomeric position andC, O, SandN-glycosides,4and oligosaccharides5were synthesized with high stereoselectivity in our laboratory using derivatives that contain this group. However the glycosyl trifluoroacetates were found to be too reactive, and new glycosyl donors containing the trichloroacetoxy leaving group were studied. We now report a stereoselective and mild method for the synthesis of α-mannosides and related oligosaccharides from benzylated mannopyranosyl trichloroacetate (1).