Reaction of 1-O-unprotected tetra-O-acetyl-and tetra-O-benzyl-glucopyranose with N-aryl haloacetimidoyl chlorides in the presence of sodium hydride and 15-crown-5 afforded N-aryl- O-glucopyranosyl haloacetimidates. Mainly the β-anomers were obtained in this anomeric O- acylation-type reaction. The glycosyl donor properties of these haloacetimidates were investigated with 6-O-and 4-O-unprotected glucopyranosides as acceptors. The results ...