A simple methodology for the synthesis of the 2-(1H-indol-3-yl)indolin-3-one core present in various natural products is developed. This method comprises Ru(II)-catalyzed regioselective addition of indole to isatogen, along with N & horbar;O bond reduction. A range of indolin-3-one compounds incorporating a C2-indolyl unit are synthesized under catalytic conditions in good yields, including the natural products halichrome A and metagenediindole A. With the help of control experiments and density functional theory calculations, a plausible mechanism founded upon the involvement of a bimetallic Ru complex is proposed.

Foreign