CO2 as a C1 Source: B(C6F5)3-Catalyzed Cyclization of o-Phenylene-diamines To Construct Benzimidazoles in the Presence of Hydrosilane

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• 作者：Zhenbei Zhang ; Qiangsheng Sun ; Chungu Xia ; Wei Sun
• 刊名：Organic Letters
• 出版年：2016
• 出版时间：December 16, 2016
• 年：2016
• 卷：18
• 期：24
• 页码：6316-6319
• 全文大小：402K
• ISSN：1523-7052

文摘

The catalytic construction of benzimidazoles using CO₂ as a carbon source represents a facile and sustainable approach to obtaining these valuable compounds. Herein, we describe the B(C₆F₅)₃-catalyzed synthesis of benzimidazoles via cyclization of o-phenylenediamines with CO₂ and PhSiH₃. 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., ¹³C NMR) of the reaction intermediates.