Natural and Medical Sciences Research Center (NMSRC), University of Nizwa, 616, Nizwa, Sultanate of Oman.
Department of Polymer and Material Chemistry, Shahid Beheshti University, 19839-4716, Tehran, Iran.
Chempluschem. 2020 Jul;85(7):1587-1595. doi: 10.1002/cplu.202000367.
An aminopyridinium ionic liquid is presented as a green, tunable, and active metal-free one-component catalytic system for the atom-efficient transformation of oxiranes and CO to cyclic carbonates. Inclusion of a positively charged moiety into aminopyridines, through a simple single-step synthesis, provides a one-component ionic liquid catalytic system with superior activity; effective in ring opening of epoxide, CO inclusion, and stabilization of oxoanionic intermediates. An efficiency assessment of a variety of positively charged aminopyridines was pursued, and the impact of temperature, catalyst loading, and the kind of nucleophile on the catalytic performance was also investigated. Under solvent-free conditions, this bifunctional organocatalytic system was used for the preparation of 18 examples of cyclic carbonates from a broad range of alkyl- and aryl-substituted oxiranes and CO , where up to 98 % yield and high selectivity were achieved. DFT calculations validated a mechanism in which nucleophilic ring-opening and CO inclusion occur simultaneously towards cyclic carbonate formation.
一种氨基吡啶鎓离子液体被提出作为一种绿色、可调谐且高效的无金属单组分催化体系，用于高效转化环氧化物和 CO 合成环状碳酸酯。通过简单的一步合成，在氨基吡啶中引入正电荷部分，提供了一种具有优越活性的单组分离子液体催化体系；在环氧化合物的开环、CO 插入和氧阴离子中间体的稳定方面非常有效。对各种带正电荷的氨基吡啶进行了效率评估，并研究了温度、催化剂负载量和亲核试剂种类对催化性能的影响。在无溶剂条件下，这种双功能有机催化体系可用于制备 18 个由各种烷基和芳基取代的环氧化物和 CO 制备的环状碳酸酯，最高产率可达 98%，选择性高。DFT 计算验证了一种同时发生亲核开环和 CO 插入以形成环状碳酸酯的机理。
