Uncovering the Reactivity of Cobalt‐Catalyst Towards Regioselective Hydroarylation of 1,6‐Diyne via Weak‐Chelation Assisted C−H Bond Activation

Abstract

AbstractHerein, we report the reactivity of cobalt(III)‐catalyst towards hydroarylative functionalization of 1,6‐diyne, which has never been explored before. The N‐aryl lactam is the prime substrate that undergoes sp2 C−H bond activation. C−Co(III) bond formation occurs through weakly coordinating lactam group. The reaction mechanism reveals the in‐situ formation of a six‐membered cobaltacycle which undergoes further functionalization with 1,6‐diyne. Also, radical quenching experiments suggest the involvement of the ionic pathway for this conversion. In addition, hydrogen scrambling and kinetic isotope experiments support the proposed mechanism. A wide range of electronically biased substrates and reacting partners work well with this method in a highly atom‐economical fashion.