Substrate-Controlled\nDivergent Reductive Cyclization\nof 2‑Arylanilines Using CO<sub>2</sub> as a Switching Reagent

Capturing CO<sub>2</sub> is highly valued in the field\nof organic\nsynthesis, especially underdeveloped dual-CO<sub>2</sub> conversion.\nIn this study, we detail a novel reductive cyclization of 2-indolylanilines\nwith dual CO<sub>2</sub> as a difunctional reagent in the presence\nof PMHS [poly(methylhydrosiloxane)], delivering methyl-substituted\nquinoxalines. Furthermore, another chemoselective cyclization with\n2-pyrrolylanilines is also realized by converting mono-CO<sub>2</sub>. Mechanistic investigations shed light upon the fact that this substrate-controlled\ndivergence mainly depends on the formation of <i>N</i>-diacylative\nintermediates.