Reducing oligosaccharides via glycal assembly: on the remarkable stability of anomeric hydroxyl groups to global deprotection with sodium in liquid ammonia

Several partially benzylated 1-hydroxy sugars were rapidly deprotected by sodium/liquid ammonia. The terminal hemiketal linkage of the substrates remained intact under these conditions and does not generate ring-opened alditols. Peracetylated glucose and glucosamine derivatives were obtained in 64–79% isolated yields.