Departamento de Química Orgánica e Inorgánica, QUOREX Research Group, Facultad de Ciencias, Universidad de Extremadura , E-06006, Badajoz, Spain.
J Org Chem. 2014 May 2;79(9):4201-5. doi: 10.1021/jo500349g. Epub 2014 Apr 21.
An improved preparation of mesoionic heterocycles 1,3-diazolium-4-thiolates by [3 + 2] cycloadditions of münchnones with aryl isothiocyanates is reported. The process takes place with high or complete regioselectivity, and fast and clean transformations are observed under microwave heating in DMF. DFT calculations support that this cycloaddition proceeds preferably through a stepwise mechanism. Given the pattern substitution around the mesoionic ring resulting in a push-pull system, theoretical estimations predict large hyperpolarizabilities in some cases, which is typical of molecules exhibiting nonlinear optical responses.
本文报道了通过 münchnones 与芳基异硫氰酸酯的[3 + 2]环加成反应，来制备偕胺肟-4-硫代杂环的改进方法。该过程具有高或完全的区域选择性，并且在 DMF 中微波加热下观察到快速而清洁的转化。DFT 计算支持该环加成反应主要通过分步机制进行。鉴于介离子环周围的取代模式导致推-拉体系，理论估算预测在某些情况下会出现大的极化率，这是表现出非线性光学响应的分子的典型特征。
