Visible-Light-Induced Iron(III)-Catalyzed Synthesis of Unsymmetrical Bis(indolyl)methanes through Hydrogen Atom Transfer

Abstract We report a visible-light-mediated, FeCl3-catalyzed, one-pot tandem strategy for the regioselective synthesis of unsymmetrically substituted tertiary and quaternary carbon-containing 3,3′-bis(indolyl)methanes under aerobic conditions. This strategy involves the coupling of 3-arylideneindolines with indoles through a photoinduced chlorine-radical-mediated hydrogen-atom-transfer reaction. The present strategy features mild and environmentally benign reaction conditions, low cost, high yields, and tolerance of a wide range of functional groups. Furthermore, to demonstrate the synthetic value of the reaction, a naturally occurring bioactive bisindolyl(phenyl)methane was synthesized.