Visible-Light-Driven Fischer-Type Indole Synthesis: Direct Synthesis of 2-Phosphinoylindoles from Anilines

We report a visible-light-driven indole synthesis from readily available aniline derivatives that circumvents the need for toxic phenylhydrazines and harsh conditions required in traditional Fischer indole synthesis. Mechanistic studies reveal that the reaction proceeds through an intramolecular C(sp2)-H/C(sp2)-H dehydrogenative coupling pathway. Notably, we have developed a novel hydrogen-accepting oxidant that facilitates this transformation.