SOLID-STATE OXIDATION OF PHENOLS BY TETRABENZOPENTACENE ENDOPEROXIDE

Solid state oxidation of phenols with TBPA-O-2 were examined. Dependin g on the electron-releasing ability of p-substituents of phenols, diff erent products were obtained. In the case of p-alkylphenols, successiv e proton transfers occur from the phenols to TBPA-O-2 to give phenolat e anions and a pi-delocalized cation. They are coupled to give 6,15-di aryloxy TBPA. On the other hand, in the case of phenols with electron- releasing substituents (e.g. p-SCH3, p-OCH3), there occurs an electron transfer from a phenolate anion to a pi-delocalized cation which are formed through proton transfer from the phenol to TBPA-O-2. The result ed phenoxy radicals are coupled to afford dimeric products of them. Re placing process of included solvent in the crystal of TBPA-O-2 with th e substrate was monitored by a powder X-ray diffraction method.