Efficient glycosidation of a phenyl thiosialoside donor with diphenyl sulfoxide and triflic anhydride in dichloromethane.

The formation of sialic acid glycosides with a thiosialic acid derivative, diphenyl sulfoxide, and trifluoromethanesulfonic anhydride is reported. With an excess of diphenyl sulfoxide, glycal formation can be completely suppressed and excellent yields are obtained for coupling to a wide range of primary, secondary, and tertiary acceptors.