ipso-Substitution in reactions of benzyl radicals with dihalobenzenes and 1,2,4-trichlorobenzene

Article abstract of DOI:10.1016/S0040-4020(01)80164-2

Di- and tri-halobenzenes undergo ipso-substitution on reaction with benzyl radicals, generated by thermolysis of dibenzyl mercury, to give halo- and dihalo-diphenylmethanes respectively. The relative reactivities of the dihalobenzenes and of 1,2,4-trichlorobenzene are consistent with the reactions proceeding via a transition state with significant charge transfer character to give cyclohexadienyl radicals.