Tadashi Suehiro

Aromatic triphenylmethylation : Further evidence for acyloxycyclohexadienyl radical as intermediate during the reaction between diacyl peroxide and triphenylmethyl free radical in aromatic solvents

Abstract The mechanism of homolytic triphenylmethylation of aromatic substrates has been studied by the reaction between diacyl peroxide and triphenylmethyl free radical in toluene, anisole and chlorobenzene. A previously proposed mechanism, involving acyloxycyclohexadienyl radical as intermediate, has been further ascertained by comparing relative reactivities of aromatic substrate in triphenylmethylation and the ratios meta to the sum of ortho and para substituted tetraphenylmethanes formed with relative reactivities of substrates in benzoyloxylation, isopropoxycarbonyloxylation and hydroxylation, and with the ratios of the sum of ortho and para to meta acyloxylation or hydroxylation products, respectively.

Aromatic triphenylmethylation reaction between benzoyl peroxides and triphenymethyl in aromatic solvents

Abstract The formation of tetraphenylmethane derivatives by the reaction between benzoyl peroxides and triphenylmethyl in aromatic solvents has been studied. Triphenylmethylation of a solvent molecule is a reaction between benzoyloxy sigma complex and triphenylmethyl. This mechanism has been evidenced by the analysis of isomer ratios of o -, m -, and p -methoxytetraphenylmethanes. These isomer ratios were controlled by the ratios of isomeric benzoyloxy-anisole sigma complexes, which were influenced by the polarities of solvents to give more o - and p - isomeric sigma complexes. If the polarity of solvent increases, triphenylmethyl and benzoyloxy radicals show ionic properties and hence triphenylmethylation takes place in ionic type.