Selective synthesis of anomeric α-glycosyl acetamides via intramolecular Staudinger ligation of the α-azides

α-Glycosyl azides can be transformed into the corresponding α-glycosyl acetamides with complete retention of configuration via reduction–acylation (Staudinger ligation) reactions using specifically functionalized phosphines. The α-acetamides of per-O-benzylated-fucose, per-O-benzylated-glucose and per-O-benzylated-galactose were selectively synthesized by this process.