Etude du mécanisme de la transformation photochimique d'alkylarènesulfonamido-2 cyclohexène-2 one en alkylamino-2 aryl-3 cyclohexène-2 one

When excited in their triplet excited state 2-arenesulfanamido-2-cyclohexenones lead to a very efficient desulfonation reaction and to migration of the aryl substituent. A wavelength effect was observed on the desulfonation product from direct irradiations. Furthermore, at 254 nm, a concentration effect and a quantum yield higher than unity indicate that a radical chain component was involved. The mechanism of this reaction is discussed taking into account the intramolecular character of the aryl migration.