Efficient activation of glycosyl N-(phenyl)trifluoroacetimidate donors with ytterbium(III) triflate in the glycosylation reaction

The mild, moisture-stable and cheap catalyst Yb(OTf)3 activates glycosyl N-(phenyl)trifluoroacetimidates in the stereoselective synthesis of 1,2-trans and 1,2-cis glycosides. A suitable choice of the reaction solvent led to good yields and stereoselectivity ratios. The protocol was successfully applied to acceptors and donors both exhibiting a wide range of reactivity.