5-Deoxy glycofuranosides by carboxyl group assisted photoinduced electron-transfer deoxygenation

In connection with the development of practical methods for the synthesis of deoxy sugars, a photoinduced electron-transfer (PET) reaction using 9-methylcarbazole (MCZ) as photosensitizer was applied to a 2-O-(3-trifluoromethyl)benzoylated derivative of d-galacturonic acid. The carboxylic group efficiently assists α-deoxygenation, the required irradiation time being significantly shorter than that in the absence of it. The photochemical reaction was also used for the deoxygenation of d-glucurono-6,3-lactone derivatives, providing in both cases the convenient routes for the synthesis of 5-deoxy-hexofuranosides and intermediate compounds for the synthesis of natural products, avoiding the use of metal hydrides.