Reinvestigation of the C5-acetamide sialic acid donor for alpha-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 alpha-sialylation under microfluidic conditions. The N-phenyltrifluoroacetimidate donor was efficiently mixed with an appropriate amount of TMSOTf to produce the alpha(2-6) and alpha(2-3)-sialylation products of galactose and glucosamine acceptors in excellent yields and with nearly perfect a-selectivity.