Sialic acid is a kind of important sugar acid compound, which has many biological functions. The reaction conditions of sialylation reactions are harsher than the common glycosylation reactions, the stereoselectivities are usually poor, and the configuration of anomeric carbon is difficult to control. Whether α glycosidic bond can be constructed efficiently in sialylation reactions is one of the important criteria to evaluate the reaction quality. Study of sialylation methods generally relates to following areas: the use of different leaving groups at C-2, participation of auxiliary groups at C-1 and C-3, the modification of protec-tive group of NHAc at C-5 and the development of some new promoters. In recent years, these research ar-eas, especially the study of protective group of NHAc at C-5, have made important progress. Herein, we pre-dominately make a summary and review on the new progress of sialylation methods.

Key words: glycosylation, oxazolidone, sialic acid