Zhu Yi-Shuo, Shi Benyi, Fang Ran, Wang Xiaoxuan, Jing Huanwang
State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, P. R. China.
Org Biomol Chem. 2014 Aug 14;12(30):5773-80. doi: 10.1039/c4ob00600c. Epub 2014 Jun 30.
A palladium-catalyzed direct C-H arylation of various imidazo[2,1-b]thiazoles with a range of aryl bromides under microwave irradiation is described. 6-Phenyl substituted imidazo[2,1-b]thiazoles could be regioselectively C-5 arylated using the developed protocol. The utility of this method enables the representative coupling product to be achieved by a sequential one-pot reaction. Density functional theory (DFT) calculations show that this arylation proceeds via a concerted metalation-deprotonation (CMD) pathway, which is in agreement with our experimental results. This work provides a convenient access to a variety of biologically active imidazo[2,1-b]thiazole derivatives. Also, it enriches the mechanism study of site-selective C-H arylation in fused heterocycles, and offers a valuable guide to design highly efficient catalytic systems for the preparation of similar compounds.
描述了在微波辐射下，钯催化各种咪唑并[2,1 - b]噻唑与一系列芳基溴的直接C - H芳基化反应。使用所开发的方法，6 - 苯基取代的咪唑并[2,1 - b]噻唑可以区域选择性地进行C - 5芳基化。该方法的实用性使得代表性的偶联产物能够通过连续的一锅反应实现。密度泛函理论（DFT）计算表明，这种芳基化反应通过协同金属化 - 去质子化（CMD）途径进行，这与我们的实验结果一致。这项工作为制备各种具有生物活性的咪唑并[2,1 - b]噻唑衍生物提供了一种便捷的方法。此外，它丰富了稠合杂环中位点选择性C - H芳基化的机理研究，并为设计用于制备类似化合物的高效催化体系提供了有价值的指导。
