Photoinduced electron transfer and chemical α-deoxygenation of d-galactono-1,4-lactone. Synthesis of 2-deoxy-d-lyxo-hexofuranosides Original Research Article

Two simple procedures for the synthesis of 2-deoxy-d-lyxo-hexono-1,4-lactone are described. Reductive cleavage of a 2-O-tosyl derivative of d-galactono-1,4-lactone in the presence of sodium iodide afforded the 2-deoxy derivative. On the other hand, α-deoxygenation of d-galactono-1,4-lactone was easily achieved by photochemical electron transfer deoxygenation of HO-2 as the 3-(trifluoromethyl)benzoate. Methyl 2-deoxy-β-d-lyxo-hexafuranoside (‘methyl 2-deoxy-β-d-galactofuranoside’) was synthesized and tested as substrate for exo β-d-galactofuranosidase from Penicillium fellutanum. The reaction was followed by HPAEC, showing that methyl 2-deoxy-β-d-galactofuranoside was not hydrolyzed by incubation with the enzyme. Neither the 2-deoxy lactone, nor the 2-deoxy-β-d-galactofuranoside acted as inhibitors of the reaction with the 4-nitrophenyl β-d-galactofuranoside. The present and our previous results show that the hydroxyl groups at C-2, C-3 and C-6 of the galactofuranoside are essential for interaction with the exo β-d-galactofuranosidase.