Zeng Rong, Chen Peng-Hao, Dong Guangbin
Department of Chemistry, University of Texas at Austin, Austin, Texas, 78712, USA.
ACS Catal. 2016 Feb 5;6(2):969-973. doi: 10.1021/acscatal.5b02532. Epub 2015 Dec 30.
The first decarbonylative cycloaddition of less-strained cyclic ketones (isatins) with isocyanates is reported. Initiated by C-C activation, this distinct [5-2+2] transformation provides a rapid entry to access various benzimidazolidinone derivatives, through which a wide range of isocyanates can be efficiently coupled with broad functional group tolerance. A modified one-pot process, combining Curtius rearrangement and C-C activation, was also achieved by using acyl azides as the starting materials. Detailed mechanistic study revealed a surprising double-decarbonylative reaction pathway. The novel reactivity discovered in this basic research is expected to shed light on developing new heterocycle formation methods through a C-C/isocyanate coupling.
报道了张力较小的环状酮（异吲哚酮）与异氰酸酯的首例脱羰环加成反应。该独特的[5-2+2]转化反应由碳-碳活化引发，可快速合成各种苯并咪唑啉酮衍生物，能使多种异氰酸酯高效偶联，且具有广泛的官能团耐受性。通过使用酰基叠氮化物作为起始原料，还实现了一种结合库尔提斯重排和碳-碳活化的改进一锅法。详细的机理研究揭示了一条惊人的双脱羰反应途径。这项基础研究中发现的新反应活性有望为通过碳-碳/异氰酸酯偶联开发新的杂环形成方法提供思路。
