A concise synthesis of 4-nitrophenyl 2-azido-2-deoxy- and 2-acetamido-2-deoxy-d-mannopyranosides

4-Nitrophenyl 3,4,6-tri-O-acetyl-2-azido-2-deoxy-α- and β-d-mannopyranosides were prepared from methyl 4,6-O-benzylidene-α-d-glucopyranoside and 1,3,4,6-tetra-O-acetyl-α-d-glucopyranose, respectively. Chemoselective reduction of both azides with hydrogen sulfide readily afforded 4-nitrophenyl 2-acetamido-4,6-di-O-acetyl-2-deoxy-α-d- and -β-d-mannopyranosides in higher yields than reduction with triphenylphosphine or a polymer-supported triarylphosphine. Subsequent de-O-acetylation yielded 4-nitrophenyl 2-acetamido-2-deoxy-α-d-mannopyranoside and 4-nitrophenyl 2-acetamido-2-deoxy-β-d-mannopyranoside in 20% and 44% overall yields, respectively.