1,2-Cis Selective Glycosylation with Glycosyl Fluoride by Using a Catalytic Amount of Trifluoromethanesulfonic Acid (TfOH) in the Coexistence of Molecular Sieve 5Å (MS5Å)

Stereoselective glycosylation of several glycosyl acceptors with 2,3,4,6-tetra-O-benzyl-β-D-glucopyranosyl fluoride was successfully carried out in diethyl ether by using a catalytic amount of trifluoromethanesulfonic acid (TfOH) in the coexistence of molecular sieve 5A (MS5A) to afford predominantly the corresponding α-linked disaccharides in high yields, which was applied to one-pot sequential syntheses of trisaccharides.