Mn(I)‐NNSe Pincer Complex Catalyzed Regioselective Synthesis of Bisindolylmethanes under Base and Solvent‐Free Conditions

Abstract Here, we present a catalytic, regioselective synthesis of bisindolylmethanes through the reaction of indoles and benzyl alcohol derivatives mediated by metal‐ligand cooperative catalysis. The reaction is catalyzed by an earth‐abundant manganese‐NNSe pincer complex without the need for base, solvent, additives, or hydrogen acceptors yielding water and dihydrogen as environmentally friendly by‐products. Notably, C‐3 and N ‐alkylation of indole, commonly observed in similar reactions were not detected. Mechanistic studies suggest that metal‐ligand cooperative catalysis by the Mn(I)‐NNSe pincer complex initiates the conversion of benzyl alcohol to benzaldehyde through dihydrogen elimination, which subsequently facilitates the synthesis of bisindolylmethane derivatives. To highlight the practical utility of this method, a wide range of substrates can be activated with low catalyst loading under mild reaction conditions.