Chemical synthesis of the branched pentasaccharide 6′-α-maltosyl-maltotriose (15) is reported, based on the use of one synthon as a glycosyl acceptor and another synthon as a glycosyl donor. The synthon used as glycosyl acceptor was phenyl 2, 3, 6-tri-O-benzyl-1-thio- β-d-glucopyranoside (7) and was synthesized from d-glucose with phenyl 2, 3-di-O-acetyl-4, 6-O-benzylidene-1-thio-β-d-glucopyranoside and phenyl 2, 3-di-O-benzyl-4, 6-O- ...