FeCl3-Assisted Niobium-Catalyzed Cycloaddition of Nitriles and Alkynes: Synthesis of Alkyl- and Arylpyrimidines Based on Independent Functions of NbCl5 and FeCl3 Lewis Acids
FeCl3-Assisted Niobium-Catalyzed Cycloaddition of Nitriles and Alkynes: Synthesis of Alkyl- and Arylpyrimidines Based on Independent Functions of NbCl5 and FeCl3 Lewis Acids
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DOI：
10.1021/acs.orglett.7b02708
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发表时间：
2017-10-20
期刊：
影响因子：
5.2
通讯作者：
Obora, Yasushi
中科院分区：
文献类型：
--
作者：
Fuji, Maito;Obora, Yasushi
NbCl5 催化腈与炔的[2+2+2]环加成反应用于合成嘧啶衍生物。在此反应中，使用单独的路易斯酸，即 NbCl5 和 FeCl3，是使用催化量的 NbCl5 实现反应的关键策略。使用 FT-IR 光谱研究了两种路易斯酸的作用。结果表明，NbCl5 是腈活化的有效路易斯酸催化剂，而 FeCl3 对嘧啶表现出更强的路易斯酸性，将 NbCl5 释放到催化循环中。
NbCl5-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 NbCl5 and FeCl3, is a key strategy for achieving the reaction using a catalytic amount of NbCl5. The roles of the two Lewis acids were investigated using FT-IR spectroscopy. The results showed that NbCl5 served as an efficient Lewis acid catalyst for nitrile activation, whereas FeCl3 showed stronger Lewis acidity toward pyrimidines, releasing NbCl5 into the catalytic cycle.