A density functional study of chiral phosphoric acid-catalyzed direct arylation of trifluoromethyl ketone and diarylation of methyl ketone: reaction mechanism and the important role of the CF3 group
作者:Aiping Fu、Wei Meng、Hongliang Li、Jing Nie、Jun-An Ma
DOI:10.1039/c3ob42157k
日期:——
The detailed mechanism of the chiral phosphoric acid-catalyzed diarylation reaction between acetophenone and indole has been investigated by DFT methods and compared with that of the reaction between 2,2,2-trifluoroacetophenone and indole. The calculated results confirm our previous hypothesis that the CF3 group in the ketone plays a perfect double role in activating the substrate and stabilizing the
通过DFT方法研究了手性磷酸催化苯乙酮与吲哚之间二芳基化反应的详细机理,并将其与2,2,2-三氟苯乙酮与吲哚之间的反应机理进行了比较。计算结果证实了我们先前的假设,即酮中的CF 3基团在活化底物和稳定叔醇的单一芳基化产物中起着完美的双重作用。还证明了甲基酮的CH 3基团中的F取代比例不同(CH 3− n F n,n= 0、1、2、3)对拟议的二芳基化过程的键脱水步骤的活化能有不同的影响,并确定后续的重芳基化是继续进行还是被抑制。通过我们在80°C下进行的其他实验已验证了在较高的反应温度下可以克服二芳基化反应的决定速率脱水步骤中CF 3和CHF 2酮的阻障性的计算预测。此外,已经用两层ONIOM方法研究了手性磷酸催化的三氟甲基酮的单芳基化的高对映选择性。实验观察到的对映异构体过量可以成功地合理化。