Ionic Liquid-Catalyzed C鈥揝 Bond Construction using CO2 as a C1 Building Block under Mild Conditions: A Metal-Free Route to Synthesis of Benzothiazoles

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• 作者：Xiang Gao ; Bo Yu ; Zhenzhen Yang ; Yanfei Zhao ; Hongye Zhang ; Leiduan Hao ; Buxing Han ; Zhimin Liu
• 刊名：ACS Catalysis
• 出版年：2015
• 出版时间：November 6, 2015
• 年：2015
• 卷：5
• 期：11
• 页码：6648-6652
• 全文大小：327K
• ISSN：2155-5435

文摘

The construction of the C鈥揝 bond using CO₂ as a C1 feedstock can be considered as a green route for the synthesis of S-containing compounds and is of great significance. Herein, we report the acetate-based ionic liquids (ILs)-catalyzed synthesis of benzothiazoles via cyclization of 2-aminothiophenols with CO₂ and hydrosilane under mild conditions (e.g., 60 掳C, 0.5 MPa). It was found that the IL (e.g., 1-butyl-3-methylimidazolium acetate, [Bmim][OAc]) served as a multifunctional catalyst with activating CO₂ and hydrosilane to form a formoxysilane intermediate, as well as simultaneously activating 2-aminothiophenols through a hydrogen bond, finally resulting in the production of benzothiazoles. [Bmim][OAc] showed the best performance, and a series of benzothiazoles were obtained in high yields. To the best of our knowledge, this is the first protocol for the synthesis of benzothiazoles using CO₂ as a C1 building block under metal-free and mild conditions.