Effect of complexation of silver ion with the glycosyl donor and acceptor on the regio- and stereo-selectivity in the β-mannopyranosylation of 1,3-di-N-benzyloxycarbonyl-2-deoxystreptamine using silver triflate as a promoter in tetrahydrofuran

Abstract A pseudodisaccharide, a 5- O -(β- d -mannopyranosyl)-2-deoxystreptamine derivative, was obtained preferentially when 2,3,4-tri- O -allyl-6- O -benzyl-α- d -mannopyranosyl chloride ( 1 ) was used as the glycosyl donor for coupling with 1,3-di- N -benzyloxycarbonyl-2-deoxystreptamine ( 2 ) using silver triflate as a promoter in tetrahydrofuran. Complexation of the glycosyl acceptor and the allyl protecting group of the glycosyl donor with the promoter proved important for the regio- and stereo-selective formation of the β-mannopyranosyl linkage.