Ruthenium-Catalyzed<i>meta</i>-Selective C−H Mono- and Difluoromethylation of Arenes through<i>ortho</i>-Metalation Strategy
作者:Zhong-Yuan Li、Liang Li、Qi-Li Li、Kun Jing、Hui Xu、Guan-Wu Wang
DOI:10.1002/chem.201700354
日期:2017.3.8
Mechanistic studies indicate that a reaction pathway involving palladium‐initiated radical species is involved in the catalytic cycle. The new dual catalytic system consisting of compatible ruthenium(II) and palladium(0) complexes enables the key processes of C−H activation and mono‐/difluoromethyl‐radical formation to occur and achieves the meta‐selective functionalization efficiently. In addition, the present
建立了钌催化配体定向的间位选择性CH单氟和二氟甲基化的第一个例子,提供了多种新的间位单或二氟甲基化的2-苯基吡啶,2-苯基嘧啶和1-苯基吡唑的产率中等至良好。这种新的转化具有广泛的底物范围,良好的官能团耐受性和高效率,并且为合成单氟甲基化和二氟甲基化的芳烃提供了一种实用的方法。机理研究表明,涉及钯引发的自由基物种的反应途径参与了催化循环。由兼容钌(II)和钯的新的双催化体系(0)配合物使C-H的关键过程激活和单- /二氟甲基-自由基的形成发生并且实现了元有效地-选择性官能化。此外,本协议还可以扩展到非氟甲基化。