Synthesis of a model of an inner chain of cell-wall proteoheteroglycan isolated from Piricularia oryzae: Branched d-mannopentaosides

Abstract

Efficient syntheses are described of the branched d-mannopentaosides methyl 2,6-di- O-(2- O-α- d-mannopyranosyl-α- d-mannopyranosyl)α- d-mannopyranoside and methyl 2,4-di- O-(2- O-α- d-mannopyranosyl-α- d-mannopyranosyl)-α- d-mannopyranoside, starting from the glycosyl acceptors methyl 3,4-di- O-benzyl-α- d-mannopyranoside and methyl 3,6-di- O-benzyl-α- d-mannopyranoside, and employing the protected d-mannotriosides methyl 3,4-di- O-benzyl-2,6-di- O-(3,4,6-tri- O-benzyl-α- d-mannopyranosyl)-α- d-mannopyranoside, and methyl 3,6-di- O-benzyl-2,4-di- O-(3,4,6-tri- O-benzyl-α- d-mannopyranosyl)-α- d-mannopyranoside as key intermediates.