Synthesis of Antigenic Tetrasaccharide Repeating Unit by Employing Cationic Gold(I)-Catalyzed Glycosylation Involving Glycosyl -1,1-Dimethylpropargyl Carbamate Donors.

Synthesis of an antigenic tetrasaccharide repeating unit of the -polysaccharide of lipopolysaccharide has been accomplished. Those four monosaccharides were assembled stereoselectively by employing our recently developed cationic gold(I)-catalyzed glycosylation methodology involving various glycosyl -1,1-dimethylpropargyl carbamate donors. The newly formed α-anomeric stereochemical configuration was controlled by the axial C2-OBz of the glycosyl donors via anchimeric assistance.