Regioselective sulfonylation of 6,1′,6′-tri- O-tritylsucrose through dibutylstannylation: synthesis of 4′- O-sulfonyl derivatives of sucrose

Abstract

3- O-Mesyl-1,6-di- O-trityl-β- d-fructofuranosyl-(2→1)-6- O-trityl-α- d-glucopyranoside ( 3) was synthesized via stannylation of 6,1′,6′-tri- O-tritylsucrose with dibutyltin oxide in benzene, followed by treatment of the crude product with methanesulfonyl chloride in the presence of triethylamine in dichloromethane at 0 °C. A similar treatment of the tri-tritylsucrose in toluene, instead of benzene, yielded 4- O-mesyl-1,6-di- O-trityl-β- d-fructofuranosyl-(2→1)-6- O-trityl-α- d-glucopyranoside ( 4) as the major product. The X-ray crystal structure of the corresponding acetyl derivative, 3- O-acetyl-4- O-mesyl-1,6-di- O-trityl-β- d-fructofuranosyl-(2→1)-2,3,4-tri- O-acetyl-6- O-trityl-α- d-glucopyranoside ( 5), confirms the position and stereochemistry of the methanesulfonyl group at C-4 of the fructofuranosyl ring.