A Novel Approach to N-Acetyl-neuraminic Acid-Containing Oligosaccharides. Synthesis of a Glycosyl Donor Derivative of α-N-Acetyl-D-neuraminyl- (2-6) -D-galactose

O-(Methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-α-D-glycero-D-galacto-2-nonulopyranosylonate)-(2-6)-(3,4-di-O-benzyl-2-O-(4-nitrobenzoyl)-α-D)-galactopyranosyl bromide was synthesized and used as a disaccharide glycosyl donor in the synthesis of sialylactose α-D)-Neup5Ac-(2-6)-β-D-Galp-(1-4)-D-Glc.