Reinvestigation of the C5-acetamide sialic acid donor for α-selective sialylation: practical procedure under microfluidic conditions.

Despite the previous literature describing the "low-to-modest" efficiency, the readily available C5-acetamide donor was reinvestigated for its use in α-sialylation under microfluidic conditions. The N-phenyltrifluoroacetimidate donor was efficiently mixed with an appropriate amount of TMSOTf to produce the α(2-6) and α(2-3)-sialylation products of galactose and glucosamine acceptors in excellent yields and with nearly perfect α-selectivity.