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.

A convenient and efficient Cu(OAc)2-mediated N-heteroannulation reaction of [60]fullerene with N-sulfonylated o-amino-aromatic methyl ketones or O-alkyl oximes has been reported for the synthesis of novel and scarce [60]fullerene-fused tetrahydroazepinones and -azepinonimines in a highly selective manner. Moreover, a possible mechanism involving two pathways is proposed on the basis of the experimental observations.

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