2-氰咪唑盐单电子还原的发散自由基、二聚化和卡宾形成

IF 2.7 4区 化学 Q1 CHEMISTRY, ORGANIC
Jawon Jang, Jaelim Kim, Prof. Eunsung Lee
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引用次数: 0

摘要

腈是构建含氮分子不可或缺的合成基石,在制药、农用化学品和材料科学中有着广泛的应用。虽然它们传统的双电子还原可以转化为胺、羧酸和醛,但它们的单电子还原途径(导致自由基形成)在很大程度上仍未被探索。本文报道了2-氰咪唑盐的合理合成,并对其单电子还原途径进行了研究。还原后,这些化合物产生有机自由基和游离碳烯。值得注意的是,自由碳烯的形成是通过介离子碳烯(MIC)中间体的亲电氰化物转移过程发生的。我们进一步证明了咪唑n取代基的空间体积在决定自由基稳定性方面起着关键作用。具有空间体积庞大取代基的咪唑产生了持久性自由基,并用电子顺磁共振(EPR)光谱对其进行了表征。相反,用体积较小的N取代基加热自由基会导致二聚化,形成新的C(sp)─C(sp2)和C(sp2)─N键。密度泛函理论(DFT)计算支持对其机制的深入了解。
本文章由计算机程序翻译,如有差异,请以英文原文为准。

Divergent Radical, Dimerization, and Carbene Formation from One-Electron Reduction of 2-Cyanoimidazolium Salts

Divergent Radical, Dimerization, and Carbene Formation from One-Electron Reduction of 2-Cyanoimidazolium Salts

Divergent Radical, Dimerization, and Carbene Formation from One-Electron Reduction of 2-Cyanoimidazolium Salts

Divergent Radical, Dimerization, and Carbene Formation from One-Electron Reduction of 2-Cyanoimidazolium Salts

Divergent Radical, Dimerization, and Carbene Formation from One-Electron Reduction of 2-Cyanoimidazolium Salts

Nitriles are indispensable synthetic building blocks for the construction of nitrogen-containing molecules with broad applications in pharmaceuticals, agrochemicals, and materials science. While their conventional two-electron reductions enable transformations into amines, carboxylic acids, and aldehydes, their one-electron reduction pathways, which lead to radical formation, remain largely unexplored. In this study, we report the rational synthesis of 2-cyanoimidazolium salts and investigate their one-electron reduction pathways. Upon reduction, these compounds yield both organic radicals and free carbenes. Notably, the free carbene formation occurs via electrophilic cyanide transfer proceeding through a mesoionic carbene (MIC) intermediate. We further demonstrate that the steric bulkiness of imidazolium N-substituents plays a critical role in determining radical stability. The imidazolium with a sterically bulky substituent generates the persistent radical, which is characterized by electron paramagnetic resonance (EPR) spectroscopy. In contrast, heating the radical with a less bulky N-substituent leads to dimerization, forming new C(sp)─C(sp2) and C(sp2)─N bonds. Insights into their mechanism are supported by density functional theory (DFT) calculations.

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来源期刊
CiteScore
4.70
自引率
3.70%
发文量
372
期刊介绍: Organic chemistry is the fundamental science that stands at the heart of chemistry, biology, and materials science. Research in these areas is vigorous and truly international, with three major regions making almost equal contributions: America, Europe and Asia. Asia now has its own top international organic chemistry journal—the Asian Journal of Organic Chemistry (AsianJOC) The AsianJOC is designed to be a top-ranked international research journal and publishes primary research as well as critical secondary information from authors across the world. The journal covers organic chemistry in its entirety. Authors and readers come from academia, the chemical industry, and government laboratories.
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