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

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-Galf-(1→2)[β-d-Galf-(1→3)]-d-Galol, that contains Galf units in both anomeric configurations, is also reported. These are the first synthetic oligosaccharides with α-d-Galf, previously found in natural products.

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