Synthesis of Cyclic Organic Carbonates Using Atmospheric Pressure CO2 and Charge-Containing Thiourea Catalysts
Synthesis of Cyclic Organic Carbonates Using Atmospheric Pressure CO2 and Charge-Containing Thiourea Catalysts
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DOI：
10.1021/acs.joc.8b01374
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发表时间：
2018-09-07
影响因子：
3.6
通讯作者：
Kass, Steven R.
中科院分区：
文献类型：
--
作者：
Fan, Yang;Tiffner, Maximilian;Kass, Steven R.
从合成、环境和绿色化学的角度来看，环氧化物与CO2的环加成合成环状五元环有机碳酸酯引起了广泛的兴趣，而开发用于这些转化的有效催化剂是一个持续的挑战。据报道，一系列八种含电荷的硫脲盐可在温和条件（即 60 摄氏度和大气 CO2 压力）下催化这些反应。还进行了底物范围和机理研究，测量了同位素效应，并分离了反应性中间体，揭示了硫脲催化剂在环氧化物环裂解中充当亲核试剂的令人惊讶的途径。
Cycloadditions of epoxides with CO2 to synthesize cyclic five-membered ring organic carbonates are of broad interest from a synthetic, environmental, and green chemistry perspective, and the development of effective catalysts for these transformations is an ongoing challenge. A series of eight charge-containing thiourea salts that catalyze these reactions under mild conditions (i.e., 60 degrees C and atmospheric CO2 pressure) are reported. Substrate scope and mechanistic studies were also carried out, isotope effects were measured, and a reactive intermediate was isolated revealing a surprising pathway in which a thiourea catalyst serves as anucleophile in the cleavage of the epoxide ring.