Internuclear cyclisation. Part XXVI. Photolysis of 2-iodo-N-methylbenzanilide in benzene

Abstract

Photolysis of 2-iodo-N-methylbenzanilide gives products which arise by cyclisation reactions of the radical derived by loss of an iodine atom, and which are similar to those formed from the copper-catalysed decomposition of the corresponding diazonium fluoroborate. The observed slight differences between the two reactions are largely attributable to the formation of iodine and hydrogen iodide in the photochemical reaction, which intercept various intermediates. The success of internuclear cyclisation in these systems appears to depend on the preference of the aryl radical precursors for conformations in which the two aryl groups are cis[e.g.(1a)].