Highly α-Stereoselective One-pot Sequential Glycosylation Using Glucosyl Thioformimidate Derivatives

Abstract
Several trisaccharides were prepared by efficient highly α-stereoselective one-pot sequential glycosylation using glucosyl p-trifluoromethylbenzylthio-p-trifluoromethylphenyl formimidates (abbreviated to: glucosyl thioformimidates) in the presence of a catalytic amount of TfOH. Factors that controlled the high α-stereoselectivity were determined by characteristic properties of thioformimidate groups contained both in glucosyl donor and acceptor.