AuCl3催化2-(1-炔基)-2-烯基酮合成多取代呋喃的机理

采用密度泛函理论的B3LYP泛函对AuCl₃催化的2-(1-炔基)-2-烯基酮与亲核试剂反应的机理进行了研究, 得到了反应的最优路径. 结果表明, 整个反应的决速步骤是羟基H转移到AuCl₃的配体Cl上, 其活化能为49.3 kJ·mol^-1. 通过计算发现, 催化剂AuCl₃的配体Cl原子在反应中有重要的作用, 它不仅稳定配合物, 而且直接参与反应, 协助质子的转移, 显著降低质子转移的活化能(由71.5 kJ·mol^-1降低到49.3 kJ·mol^-1). 另外还讨论了HBF₄不能催化此反应的可能原因, 计算结果与实验结果一致.

Mechanism of AuCl3-Catalyzed Synthesis of Highly Substituted Furans Based on 2-(1-Alkynyl)-2-alken-1-ones

We investigated the mechanism of the AuCl3-catalyzed synthesis of highly substituted furans from 2-(1-alkynyl)-2-alken-1-ones with nucleophiles using the density functional theory (DFT) with B3LYP function,and obtained the optimal pathway.The rate-determining step of the cyclization is H-migration from the hydroxy group to a ligand Cl of AuCl3 with a 49.3 kJ · mol-1 energy barrier.The calculated results show that the ligand Cl of AuCl3 plays an important role in the reaction,which stabilizes the catalyst and is also directly involved in the reaction.The active energy of proton transfer decreases from 71.5 to 49.3 kJ · mol-1 by assisting the proton transfer.In addition,the reason why HBF4 cannot catalyze the cyclization of 2-(1-alkynyl)-2-alken-1-ones is also discussed in this work.The theoretical results are consistent with the experimental observations.