Synthesis of the Staphylococcus aureus Strain M Capsular Polysaccharide Repeating Unit

摘要

The synthesis of the Staphylococcus aureus strain M capsular polysaccharide repeating unit is reported. A postglycosylation oxidation strategy was utilized for the construction of the alpha-galactosaminuronic acid linkages, relying on a stereoselective 2-azido-4,6-O-di-tent-butylsilylidene galactopyranoside donor, for which the selectivity was assessed by model glycosylations. The a-fucosamine linkage was installed stereoselectively, using a reactive 2-azidofucosyl donor. An unexpected glycosidic bond cleavage during the TEMPO/PhI(OAc)(2)-mediated oxidation of a disaccharide intermediate was circumvented by a TEMPO/PhI(OAc)(2)-Pinnick oxidation protocol.