(1) MECHANISM OF FREE RADICAL CYCLIZATION THROUGH AROMATIC SUBSTITUTION

Free radical cyclizations of the 4-phenylbutyl radical and analogues carrying naphthyl and vinyl groups instead of phenyl have been studied. A typical reac-tion scheme is given below involving closures to five- and six-membered rings. Competition rate studies for the various types of ring closure were performed with deuterated analogues. The results can be used as an efficient mechanistic tool for other radical processes, as exemplified for the Kornblurn reaction between x-substituted p-nitrobenzyl chlorides with the anion of benzylcyanide in a two.phase system. The nature of (cyclic) byproducts supports and con-firms the radical chain mechanism for such substitutions