A one-pot synthesis of 2,2′-disubstituted diindolylmethanes (DIMs) via a sequential Sonogashira coupling and cycloisomerization/C3-functionalization of 2-iodoanilines†
A Pd(II)–Ag(I) catalyzed highly efficient synthesis of diindolylmethane has been developed. This transformation consists of a one-pot sequential Sonogashira coupling (and desilylation) followed by cycloisomerization/C3-functionalization of 2-iodoanilines. Six new bonds (four C–C and two C–N) are formed in a one-pot fashion. A variety of diindolylmethanes were obtained in excellent yields (up to 94%) under mild reaction conditions and this strategy is amenable to gram scale synthesis also. The products were transformed into various synthetically useful compounds.