Chemical synthesis of β- d-psicofuranosyl disaccharides

Abstract

Disaccharides composed of a β- d-psicofuranosyl unit were prepared by the glycosylation reaction of monosaccharide acceptors including three 2,3,4,6-tetra- O-protected hexopyranoses with a d-psicofuranosyl benzyl phthalate derivative ( 4). A β- d-psicofuranosidic bond was formed by the TMSOTf-promoted reaction with high selectivity. Removal of the O-protecting groups from the resulting α- d-hexopyranosyl β- d-psicofuranosides furnished the first chemical synthesis of α- d-gluco-, α- d-galacto-, and α- d-mannopyranosyl β- d-psicofuranosides. The common β- d-psicofuranosyl donor 4 was derived efficiently from d-psicose in five steps.