An efficient method for the preparation of 2-deoxy-glycopyranosides was developed by using 2,3-anhydrothioglycosides as the glycosylating agents.The reaction proceeded by the Cu(OTf)_2-mediated rearrangement of 2,3-anhydrothiosugars.And high anomeric stereoselectivity was achieved.The disclosed methodology may find applications in the preparation of many biologically important 2-deoxy-glycosides.
We report a novel P-directing effect of imidazolium based ionic liquid,which was observed when we conducted the glycosylation of a 6-O-acetyl-2,3,4-tri-O-benzyl-mannose trichloroacetimidate donor with a modified ionic liquid support acceptor. The mechanism was investigated and a hypothesis was proposed.After optimization of the reaction conditions,an innovative method for the selective construction of 1,2-cis-β-D-mannopyranosyl linkage was developed.
