Expedient synthesis of a series of N-acetyllactosamines

A series of poly-N-acetyllactosamines representative of those found on complex N-glycans was synthesized for use in the kinetic characterization of recently cloned glycosyltransferases. The syntheses involved the iterative addition of a selectively protected N-acetyllactosaminyl donor to an octyl α- -mannopyranosyl-1,6-β- -mannopyranoside acceptor, followed by deprotection. In addition, non-reducing galactosyl residues were removed with β-galactosidase to furnish GlcNAc terminated compounds. In this manner tetra- to octasaccharides were efficiently produced.