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 alpha-D-mannopyranosyl-1,6-beta-D-mannopyranoside acceptor, followed by deprotection. In addition, non-reducing galactosyl residues were removed with beta-galactosidase to furnish GlcNAc terminated compounds. In this manner tetra- to octasaccharides were efficiently produced.