The Thioglycoside and Glycosyl Phosphite of 5-Azido Sialic Acid: Excellent Donors for theα-Glycosylation of Primary Hydroxy Groups

5-Azido sialyl donors with O-acetyl protecting groups are useful α-selective glycosylation reagents, especially for primary hydroxyl groups as acceptors. This is shown with a variety of reactions using 1 as a sialyl donor. It was also possible to synthesize NeuAcα(2→9)NeuAc as a thioglycoside donor for use in subsequent glycosylations.