Azole-Anion-Based Aprotic Ionic Liquids: Functional Solvents for Atmospheric CO₂ Transformation into Various Heterocyclic Compounds

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• 作者：Dr. Yanfei Zhao ; Yunyan Wu ; Guangfeng Yuan ; Leiduan Hao ; Xiang Gao ; Dr. Zhenzhen Yang ; Dr. Bo Yu ; Dr. Hongye Zhang and Prof. Zhimin Liu
• 刊名：Chemistry – An Asian Journal
• 出版年：2016
• 出版时间：October 6, 2016
• 年：2016
• 卷：11
• 期：19
• 页码：2735-2740
• 全文大小：950K
• ISSN：1861-471X

文摘

The chemical transformation of atmospheric CO₂ is of great significance yet still poses a great challenge. Herein, azole-anion-based aprotic ionic liquids (ILs) were synthesized by the deprotonation of weak proton donors (e.g., 2-methylimidazole, 4-methylimidazole, and 2,4-dimethylimidazole) with tetrabutylphosphonium hydroxide, [Bu₄P][OH]. We found that these ILs, such as [Bu₄P][2-MIm], could activate atmospheric CO₂ through the formation of carbamates. The resultant carbamate intermediates could further react with various types of substrate, including propargylic alcohols, 2-aminobenzonitriles, ortho-phenylenediamines, and 2-aminothiophenol, thereby producing α-alkylidene cyclic carbonates, quinazoline-2,4(1 H,3 H)-diones, benzimidazolones, and benzothiazoline, respectively, in moderate-to-good yields. Thus, we have achieved the transformation of CO₂ at atmospheric pressure, and we expect this method to open up new routes for the synthesis of various oxygen-containing heterocyclic compounds under metal-free conditions.