甲酰基甲硫酰基双烯酮异构化反应的理论研究

Theoretical studies on the isomerization reactions of formyl(thioformyl)ketene

用从头算方法对甲酰基甲硫酰基双烯酮两种形成不饱和四员杂环硫杂环丁烯酮或氧杂环丁烯酮的异构化反应进行了理论研究 ,优化得到反应途径上的反应物、过渡态和产物的构型 ,通过振动分析对过渡态进行了确认 .研究结果表明 :两个异构化反应的闭环产物均不如开环反应物稳定 ,形成硫杂环丁烯酮的反应无论从热力学还是从动力学角度都比形成氧杂环丁烯酮的反应容易 .

The two isomerization reactions of formyl(thioformyl)ketene forming two four membered unsaturated heterocycle products thietone or oxetone have been studied by using ab initio method at HF/6 31G * level.All the geometries of the stationary points on the reaction path have been optimized with the Berny energy gradient technique.The transition states were characterized by vibration frequency analysis.The results show that two reactions both proceed via one elementary step,The barrier is 65.42 or 111.17 kJ·mol -1 respectively for reaction forming thietone or reaction forming oxetone.Two products thietone and oxetone are both thermodynamically less stable then reactant formyl(thioformyl)ketene.