The use of DISAL (methyl dinitrosalicylate) glycosyl donors in efficient Lewis acid-promoted glycosylations is reported. N-Acetyl-D-glucosamine monosaccharide acceptors are successfully glycosylated at O-6 or O-4 using benzyl-and benzoyl-protected DISAL donors in CH2Cl2 or nitromethane in the presence of LiClO4. The resultant disaccharides are isolated in yields ranging from 35 to 93%. Other Lewis acids such as FeCl3, TMSOTf, or BF3· Et2O ...