The Photochemical Degradation of Diphenyl Sulfone-1-14C

Abstract

Abstract The photolysis of diphenyl sulfone-1-14C upon irradiation with 2537 Å light in benzene gave biphenyl-1-14C and benzenesulfinic acid-14C. The yields of both compounds were estimated by means of an isotope dilution method. The 14C activity of the sulfone recovered was equal to that of the sulfone employed, while that of biphenyl formed was found to have nearly one half of the 14C activity. These results reveal that the phenylation reaction by phenyl radical formed by the photolytic cleavage of the C–S bond of the sulfone is an intermolecular reaction in which benzenesulfonyl radical appears to abstract hydrogen from the intermediate cyclohexadienyl radical rather than attacking benzene. The 14C distribution indicates that the 14C activity at 1-position was found to remain at the same position of biphenyl after photolysis of the sulfone. Thus, the photolysis of diaryl sulfones in benzene followed by the oxidation of biphenyl derivatives obtained would be a convenient method for the degradation of diaryl sulfones.