α-乙酰基二硫缩烯酮在TiCl_4催化下的酰化反应机理研究

Research on Reaction Mechanism of α-Acetyl Ketendithioacetals in the Presence of TiCl_4-Catalyst

在B3LYP/6-311G(p)理论水平上研究α-乙酰基二硫缩烯酮在TiCl4催化下的酰化反应的微观反应机理.优化反应过程中的反应物、中间体、过渡态和产物的结构,同时采用了极化连续介质模型(PCM)对各个驻点进行了单点能计算以模拟在CH2Cl2溶剂中的反应过程,并且应用了自然轨道理论(NBO)和分子中的原子理论(AIM)分析了这些物质的成键特征和轨道间的相互作用.计算结果得到此反应在TiCl4催化情况下的活化能小于没有催化剂情况下的活化能,证明了在TiCl4催化剂参加的情况下有利于此反应的进行,溶剂效应也较大程度地降低了此反应的活化能.

Based on B3LYP/6-311G（p） principle,the reaction mechanism of α-acetyl ketendithioacetals in the presence of TiCl4 catalyst was investigated.PCM model was applied to calculate charge density in the bond critical points for optimized configuration of reactants,intermediates,transition states and products.Meanwhile,reaction process was also simulated in dichloronethane solution.In addition,nature bond orbital（NBO） and atoms in molecules（AIM） theories were used to discuss bond natures and orbital interactions.The computational results indicate that the activation barrier with TiCl4-catalyst is lower than that without TiCl4-catalyst which indicate that TiCl4 can promote the reaction and enhance the yield of product.Furthermore,solvent effect also decreases the barriers in a significant way.