A novel synthesis of β-d-mannopyranosyl azide by phase transfer catalysis

A simple stereoselective synthesis of per-O-benzoyl-β-d-mannopyranosyl azide from per-O-benzoyl-α-d-mannopyranosyl bromide using phase transfer catalysis was developed. The stereochemistry at C-1 of the anomeric O-benzoylated α- and β-d-mannopyranosyl azides was unambiguously established using 2D NOESY NMR spectroscopy. Pure deprotected β-d-mannopyranosyl azide was prepared by debenzoylation with sodium methoxide in methanol.