Ruthenium-catalyzed thioglycosylation: synthesis of 2,3-unsaturated-S-glycosides

The stereoselective synthesis of 2,3-unsaturated S-glycosides was accomplished by using mild and convenient protocol employing a catalytic amount of RuCl3. Various acceptors comprising aromatic, aliphatic, alicyclic, and naphthyl mercaptans were reacted smoothly with different glycals to provide regioselective C-1 S-linked glycosides in good yields (72-92%) with high alpha-anomeric selectivity (72:28-99:1). This protocol is mild enough for constructing S-linkages at anomeric position of lactose derived glycal. (C) 2015 Elsevier Ltd. All rights reserved.