A range of 1,7-diarylheptane-1,7-diones were electrooxidized in the presence of iodide ions and a base in a mixture of methanol and toluene as the reaction solvents to give the corresponding cyclized 1,2-diaroylcyclopentanes in moderate to good yields. The reactions were carried out under extremely mild reaction conditions for which the optimal amount of electrolytic current varied from 2.05–3.17 F·mol–1 depending on the substrates. The reaction presumably proceeds through a two-electron oxidation process in which the iodide ion plays an important role as the electron carrier.
Key words
electron transfer - oxidation - cyclization - ring closure - green chemistry - iodine