Preparation of Novel 1,6-Anhydro-β-lactose Derivatives for the Synthesis of N-Acetyllactosamine-Containing Oligosaccharides

Versatile intermediates for the syntheses of cell-surface oligosaccharides bearing N-acetyllactosamine units have been prepared from a readily available 1,6-anhydro-β-lactose as a key starting material. Regioselective chemical manipulations of 1,6-anhydro-β-lactose were carried out in a stepwise procedure and gave fully-protected lactosamine derivatives. It was clearly suggested that modification at C-3′ position of the galactose residue and the following introduction of a sterically hindered leaving group at C-2 position of the reducing glucose remarkably accelerated and facilitated further derivatization of this potential disaccharide material. Selective generation of hydroxyl groups at C-3, C-3′, and/or C-6′ positions proceeded smoothly in mild conditions and afforded a series of fully-functionalized disaccharide-acceptors in high yields.