Wang Fang, Zhou Qianting, Zhang Xinying, Fan Xuesen
NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China.
Advanced Research Institute and Department of Chemistry, Taizhou University, Taizhou, Zhejiang 318000, China.
J Org Chem. 2021 Sep 3;86(17):11708-11722. doi: 10.1021/acs.joc.1c01198. Epub 2021 Aug 6.
Presented herein is a novel and efficient α-C(sp)-H alkenylation of cyclic amines with maleimides. Mechanistically, this C(sp)-H/C(sp)-H cross dehydrogenative coupling (CDC) reaction involves a cascade procedure including oxidative α-amino radical formation from the cyclic amine substrate and nucleophilic addition of the in situ formed α-amino radical onto the electron-deficient carbon-carbon double bond of maleimide followed by oxidation and β-elimination. Notably, this direct α-functionalization provides an effective alternative to the conventional ionic reaction mode, in which an imine or iminium intermediate is formed to react with electron-rich coupling partners other than electron-deficient ones. In general, this method features readily available and structurally diverse substrates, a green and economical catalyst, a unique reaction pathway, mild reaction conditions, high efficiency, and excellent atom economy. This new reaction enriches the application of Fe(III)-catalyzed C(sp)-H activation and functionalization.
本文介绍了一种新颖高效的环胺与马来酰亚胺的α-C(sp)-H烯基化反应。从机理上讲，这种C(sp)-H/C(sp)-H交叉脱氢偶联（CDC）反应涉及一个级联过程，包括从环胺底物形成氧化α-氨基自由基，以及原位形成的α-氨基自由基对马来酰亚胺缺电子碳-碳双键的亲核加成，随后进行氧化和β-消除。值得注意的是，这种直接α-官能团化提供了一种替代传统离子反应模式的有效方法，在传统离子反应模式中会形成亚胺或亚胺鎓中间体，以与富电子而非缺电子的偶联伙伴反应。一般来说，该方法具有底物易于获得且结构多样、催化剂绿色经济、反应途径独特、反应条件温和、效率高以及原子经济性优异等特点。这种新反应丰富了铁（III）催化的C(sp)-H活化和官能团化的应用。
