Kim Jungwon, Hong Soon Hyeok
Department of Chemistry , College of Natural Science , Seoul National University , 1 Gwanak-ro , Seoul 08826 , South Korea . Email:
Chem Sci. 2017 Mar 1;8(3):2401-2406. doi: 10.1039/c6sc05266e. Epub 2016 Dec 20.
The first example of the use of an N-heterocyclic carbene (NHC) as an organocatalyst for the activation of isocyanides was demonstrated. On the basis of previous reports on the interaction between NHCs and isocyanides, we developed a catalytic cycle involving transient imidoyl intermediate. The reaction of ketones with isocyanides produced the corresponding enaminones with high efficiency. Control experiments suggested a novel role for the carbene in the activation of isocyanides, and a proton transfer process was found to be crucial for the generation of two activated species in the catalytic cycle. Various enaminones, some of which are not easily accessible by other methods, were synthesized in excellent yields. This study clearly demonstrates the potential of the nucleophilic activation of isocyanides in the expansion of their reactivity scope.
首次证明了使用N-杂环卡宾（NHC）作为有机催化剂来活化异腈。基于之前关于NHC与异腈之间相互作用的报道，我们开发了一个涉及瞬态亚胺酰中间体的催化循环。酮与异腈的反应高效地生成了相应的烯胺酮。对照实验表明卡宾在异腈活化中具有新的作用，并且发现质子转移过程对于催化循环中两种活化物种的生成至关重要。以优异的产率合成了各种烯胺酮，其中一些烯胺酮用其他方法不易获得。这项研究清楚地证明了异腈亲核活化在扩大其反应活性范围方面的潜力。
