Scandium triflate catalyzed thioglycosidation of glycals: A facile synthesis of 2,3-unsaturated thioglycopyranosides

Scandium triflate is found to be an efficient Lewis acid for the thioglycosidation of 3,4,6-tri-O-acetyl or benzoyl-D-glycals with various thiols to afford the corresponding 2,3-unsaturated thioglycosides in high yields with good anomeric selectivity.