Selective Synthesis of Anomeric alfa-Glycosylacetamides via Intramolecular Staudinger Ligation of the alfa-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.