A facile iron-catalyzed dual C-C bond cleavage: an approach towards triarylmethanes

A facile iron-catalyzed dual C-C bond cleaving reaction involving 1,3-dicarbonyl units along with electron-rich and sterically bulky arenes as efficient carbon-based leaving groups has been developed. The scope of the dual C-C bond breaking reaction was studied in detail using a range of nucleophiles to synthesize symmetrical triarylmethanes in good to excellent yields. We found success in isolating the intermediate of the reaction, formed via the initial C-sp(3)-C-sp(3) bond cleavage, and subsequently converted the intermediate to the final product via the C-sp(3)-C-sp(2) bond cleavage. A notable difference in the leaving aptitudes of the two carbon-based leaving groups perceived during the study enabled us to develop an application of the dual C-C bond breaking reaction for the synthesis of unsymmetrical triarylmethanes in a stepwise manner. To improve the synthetic utility, we have also fashioned a one-pot procedure to generate unsymmetrical triarylmethanes via sequential C-C bond breaking reactions. In addition to studying a novel dual C-C bond breaking reaction and providing a hint to the mechanistic pathway, the application molded from the study for the synthesis of symmetrical and especially unsymmetrical triarylmethanes may render value to the present work.