beta-Glycosides of 2,3-diazido-2,3-dideoxy-D-mannose, a synthetic precursor of a rare bacterial cell-wall building unit

2,3-Diazido-2,3-dideoxy-beta-D-mannopyranoside derivatives were synthesized in order to prepare beta-glycosides of 2,3-diacetamido-2,3-dideoxy-D-mannu ronic acid, a rare moiety of bacterial oligosaccharides, A direct glycosyl donor, 4,6-di-O-acetyl-2,3-diazido-2,3-dideoxy-alpha-D-mannopyranosyl bromi de, was prepared, and its synthetic capacity was tested in glycosylation re actions. An indirect route was also elaborated: 3-azido-3-deoxy-beta-D-gluc opyranosides were converted into beta-D-mannopyranosides. The cis vicinal d iazido function successfully tolerated the conditions of mild acidic hydrol ysis, tritylation, Jones oxidation, TEMPO oxidation, acetolysis, and bromin ation with TiBr4.