Nickel-catalyzed carbonylative domino cyclization of arylboronic acid pinacol esters with 2-alkynyl nitroarenes toward N-aroyl indoles

Abstract

A nickel-catalyzed carbonylative domino cyclization of arylboronic acid pinacol esters with 2-alkynyl nitroarenes has been developed. This tandem reaction proceeded well to synthesize various N-aroyl indole derivatives in moderate to high yields. Here, Co₂(CO)₈ has been used as the CO source and also as the co-catalyst for the cyclization step. Control experiments were performed to gain more insights into the reaction mechanism. Notably, besides acting as a reaction partner, 2-alkynyl nitroarenes may also serve as the oxidant to regenerate the active nickel catalyst.