Synthesis of α- d-Gal f-(1→2)- d-galactitol and α- d-Gal f-(1→2)[β- d-Gal f-(1→3)]- d-galactitol, oligosaccharide derivatives from Bacteroides cellulosolvens glycoproteins

Abstract

The synthesis of α- d-galactofuranosyl-(1→2)- d-galactitol, which has been isolated by reductive β-elimination from glycoproteins of Bacteroides cellulosolvens and Clostridium thermocellum, is described. The approach of selective glycosylation of an aldono-1,4-lactone by the trichloroacetimidate method was employed. The synthesis of α- d-Gal f-(1→2)[β- d-Gal f-(1→3)]- d-Galol, that contains Gal f units in both anomeric configurations, is also reported. These are the first synthetic oligosaccharides with α- d-Gal f, previously found in natural products.