Experimental observations on the regioselectivity of glycosylation of a 4,6-diol system in the β-d-mannopyranosyl unit of a N-glycan pentasaccharide core structure

► A modular strategy has been employed for the synthesis of hybrid type N-glycans. ► A hexasaccharide and two heptasaccharides have been prepared from a common precursor. ► The regioselectivity of glycosylation of a 4,6-diol system is dependent on the structure of the glycosyl donor.