CO as a C1 Source: B(CF)-Catalyzed Cyclization of o-Phenylene-diamines To Construct Benzimidazoles in the Presence of Hydrosilane.

The catalytic construction of benzimidazoles using CO as a carbon source represents a facile and sustainable approach to obtaining these valuable compounds. Herein, we describe the B(CF)-catalyzed synthesis of benzimidazoles via cyclization of o-phenylenediamines with CO and PhSiH. This metal-free catalytic route achieves the desired products in high yield under convenient reaction conditions and is applicable to a broad substrate scope. A plausible mechanism for the reaction involving a frustrated Lewis pair pathway is proposed based on spectroscopic characterization (e.g., C NMR) of the reaction intermediates.