Homolytic aromatic substitution. Part XXXIV. Major products from the reaction of benzoyl peroxide with p-disubstituted benzenes
作者:D. I. Davies、D. H. Hey、B. Summers
DOI:10.1039/j39700002653
日期:——
p-tolyl sulphide, or methyl p-tolyl sulphoxide. The major reaction is oxidation at the sulphur atom, which leads to the formation of, in addition to benzoic anhydride, arylthiomethyl and arylsulphinylmethyl benzoates from the aryl sulphides and sulphoxides respectively. There is no evidence that free radicals are involved in the reaction of benzoyl peroxide with these sulphur-containing compounds.
The reaction of four substituted bis(3-alkoxybenzoyl) peroxides (1b-e) in neat phenols (2a-e) affords mainly 8-alkoxy-6H-dibenzo[b,d]pyran-6-ones (7) and ortho-benzoyloxylation products (4) of the phenol. Diaroyl peroxides without electron-releasing meta substituents afford essentially products 4. A mechanism involving monoelectronic oxidation of the phenol by the peroxide and biaryl coupling by preferential addition of the phenol radical cation to the ortho positions to the alkoxy group of the diaroyl peroxide is suggested.