Department of Chemistry and Material Engineering, Faculty of Chemistry, Materials and Bioengineering, Kansai University , Suita, Osaka 564-8680, Japan.
Org Lett. 2017 Oct 20;19(20):5569-5572. doi: 10.1021/acs.orglett.7b02708. Epub 2017 Oct 2.
NbCl-catalyzed [2 + 2 + 2] cycloaddition of nitriles with alkynes was used to synthesize pyrimidine derivatives. In this reaction, the use of individual Lewis acids, namely NbCl and FeCl, is a key strategy for achieving the reaction using a catalytic amount of NbCl. The roles of the two Lewis acids were investigated using FT-IR spectroscopy. The results showed that NbCl served as an efficient Lewis acid catalyst for nitrile activation, whereas FeCl showed stronger Lewis acidity toward pyrimidines, releasing NbCl into the catalytic cycle.
NbCl 催化的腈与炔烃的 [2 + 2 + 2] 环加成反应被用于合成嘧啶衍生物。在这个反应中，单独使用路易斯酸，即 NbCl 和 FeCl，是使用催化量的 NbCl 实现反应的关键策略。通过傅里叶变换红外光谱研究了这两种路易斯酸的作用。结果表明，NbCl 是腈活化的有效路易斯酸催化剂，而 FeCl 对嘧啶具有更强的路易斯酸性，将 NbCl 释放到催化循环中。
