Tris(pentafluorophenyl)borane-Promoted Stereoselective Glycosylation with Glycosyl Trichloroacetimidates under Mild Conditions.

Tris(pentafluorophenyl)borane-promoted stereoselective glycosylation with trichloroacetimidate glycosyl donors is described. The reactions proceed efficiently with a wide range of acceptors, from sugar to nonsugar, under mild conditions in the presence of a catalytic amount of B(C6 F5 )3 . The perbenzylated glucosyl α-imidate provides β-selective glycosides in 70-92% yields.