The present invention relates to the field of
chemical synthesis, and disclosed is a
chemical synthesis method for
a serotype O5 O-
antigen oligosaccharide of
pseudomonas aeruginosa. In the present invention, a D-glucuronic acid building block and a D-fucosamine building block are used to construct an O-
antigen trisaccharide, wherein the stereoselective synthesis of a D-fucosamine 1,2-α-cis-
glycosidic bond relies on remote acyl participation and
reagent regulation, and the synthesis of two 2,3-diaminomannuronic acid 1,2-β-trans glycosidic bonds is realized by means of SN2
nucleophilic substitution of a C2 azido group; and by means of selective
assembly of protecting groups, orthogonal modification of modifying groups, and regulation of the reactivity of
glycosyl donors and acceptors, the preparation of a multifunctionally modified O-
antigen target
trisaccharide is successfully completed. The method of the present invention is characterized in that raw materials are cheap and easily available and the preparation method is simple and easy to repeat, and has good prospects of application in the development of vaccines against
pseudomonas aeruginosa.