Synthesis of alpha-D-Gal f-(1-->2)-D-galactitol and alpha-D-Gal f-(1-->2)[beta-D-Gal f-(1-->3)]-D-galactitol, oligosaccharide derivatives from Bacteroides cellulosolvens glycoproteins.

The synthesis of alpha-D-galactofuranosyl-(1-->2)-D-galactitol, which has been isolated by reductive beta-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 alpha-D-Gal f-(1-->2)[beta-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 alpha-D-Gal f, previously found in natural products.