Synthesis of highly condensed phospholes by the Lewis acid-assisted dehydrogenative Mallory reaction under visible light irradiation

Abstract

A photo-promoted oxidative cyclization, that is, the Mallory reaction of 2,3-diarylbenzophopholes has been developed. With the assistance of Bi(OTf)₃ Lewis acid, the reaction proceeds smoothly under visible light irradiation even without any external oxidants. The newly developed dehydrogenative conditions are compatible with various functional groups and substitution patterns, which enables the streamlined synthesis of highly condensed dibenzophosphole derivatives of potent interest in material chemistry. Moreover, experimental and computational studies unveil the detailed reaction mechanism. The preliminary optoelectronic properties of some newly synthesized compounds are also demonstrated.