Mechanism of the Benzophenone-Sensitized Photolysis ofO-Benzoyl-N-(1-naphthoyl)-N-phenylhydroxylamine in Cationic Micellar Media

Abstract

The benzophenone-sensitized photolysis of the title hydroxylamine (1) in hexadecyltrimethylammonium chloride (HTAC) micelles was found to give benzoyloxy(2,3)- and phenyl(4,5)-migrated products, along with fragmentation products, 1-naphthanilide (6) and benzoic acid (7), which were obtained exclusively from the sensitized reaction in organic media. An analysis of the effects of added benzyl alcohol on the quantum yields for the reaction in HTAC micelles showed that the benzoyloxy-migrated products are derived from the amidyl-benzoyloxyl radical pair (that is present at the micellar surface), whereas the amidyl-phenyl radical pair (that is penetrated deeply into the micellar interior) is responsible for appearance of the phenyl-rearranged products. This effect of benzyl alcohol also confirmed that the hydrogen abstraction of the amidyl and benzoyloxyl radicals takes place in competition with the spin inversion of these triplet radicals. These interpretations were substantiated by the finding that the criti...