Controlled, partial benzylation of allyl 2-acetamtdo-3- O-benzyl-2-deoxyα- d- glucopyranoside gave a mixture of the 3,4-di-, 3,6-di- ( 15), and 3,4,6-tri- O-benzyl derivatives, the major product being 15. Condensation of 15 with 2-methyl-(3,4,6-tri- O-acetyl-1,2-dideoxy-σ- d-glucopyrano)-[2,1- d]-2-oxazoline gave a disaccharide which, after purification, removal of the allyl group, and hydrogenolysis of the benzyl substituents, gave 2-acetamido-4- O-(2-acetamido-3,4,6-tri- O-acetyl-2-deoxy-β- d-glucopyranosyl)-2-deoxy-α- d-glucopyranose. This compound was further converted into di- N-acetyl-hexa- O-acetylchitobiose by acetylation, or into 2-methyl-[4- O-(2-acetamido-3,4,6-tri- O-acetyl-2-deoxy-β- d-glucopyranosyl)-3,6-di- O-acetyl- 1,2-di-deoxy-α- d-glucopyrano]-[2,1- d]-2-oxazoline, a starting material for the preparation of di- N-acetyl-α-chitobiosyl phosphate.