Highly chemo- and stereoselective glycosidation of permethacrylated O-glycosyl trichloroacetimidate reagents promoted by TMSNTf2

TMSNTf2 has been used efficiently as a promoter in glycosidation reaction involving permethacrylated Schmidt reagents. While TMSNTf2 is known to be a powerful activator for C=O double bonds, we have discovered that this reagent can activate C=N double bond selectively, even in the presence of excess CO groups of permethacrylated O-glycosyl trichloroacetimidate substrates. Glycosides are synthesized in moderate to reasonable yields with an excellent overall beta-stereoselectivity. (C) 2010 Elsevier Ltd. All rights reserved.