Bogazici University, Faculty of Arts and Sciences, Department of Chemistry, 34342, Bebek, Istanbul, Turkey.
Bogazici University, Faculty of Arts and Sciences, Department of Chemistry, 34342, Bebek, Istanbul, Turkey.
J Mol Graph Model. 2019 May;88:309-317. doi: 10.1016/j.jmgm.2019.01.016. Epub 2019 Jan 24.
In the last years, ionic liquids have been used as substitutes to common solvents since they combine good solubility properties with small vapor pressures. Herein, the Diels-Alder reactions of cyclopentadiene (CP) with acrolein, methyl acrylate and acrylonitrile in ionic liquids ([Emim][N(Tf)]), ([Hbim][N(Tf)]) and ([Bmim][OTf]) have been modeled with density functional theory to explore the effect of ionic liquids on the endo selectivity in the adducts. Besides the hydogen bonding interactions between the cation and the diene in all the structures, endo transition structures are slightly better stabilized than exo transition structures because of the favorable interactions between the H's of the CP ring and the O's of the [N(Tf)] and [OTf] anions of the IL's. In this study, B3LYP/6-31 + G* and M06-2X/6-31 + G* calculations have demonstrated that endo selectivity in the Diels-Alder reactions can be achieved in the presence of ionic liquids in agreement with experiments.
在过去的几年中，离子液体已被用作常见溶剂的替代品，因为它们结合了良好的溶解性和较小的蒸气压。在此，我们使用密度泛函理论对环戊二烯（CP）与丙烯醛、甲基丙烯酸甲酯和丙烯腈在离子液体([Emim][N(Tf)])、([Hbim][N(Tf)])和([Bmim][OTf])中的 Diels-Alder 反应进行了建模，以探索离子液体对加合物中环内选择性的影响。除了所有结构中阳离子与二烯之间的氢键相互作用外，由于 CP 环上的 H 与 IL 中的[N(Tf)]和[OTf]阴离子之间的有利相互作用，内型过渡态比外型过渡态稍微稳定。在这项研究中，B3LYP/6-31+G和 M06-2X/6-31+G计算表明，在离子液体存在下可以实现 Diels-Alder 反应的内型选择性，这与实验结果一致。
