Mechanistic Studies on the Palladium-Catalyzed Direct C-5 Arylation of Imidazoles: The Fundamental Role of the Azole as a Ligand for Palladium
作者:Luca Alessandro Perego、Laurence Grimaud、Fabio Bellina
DOI:10.1002/adsc.201500888
日期:2016.2.18
An in‐depth mechanistic study on the palladium‐catalyzed direct arylation of imidazoles at the C‐5 position is presented. The interactions of triphenylphosphine (PPh3)‐ligated aryl‐Pd species with 1,2‐dimethyl‐1H‐imidazole (dmim) have been studied in detail. In contrast with previous suggestions, phosphine‐ligated organo‐Pd species are not active and the reaction proceeds through imidazole‐ligated
提出了在C-5位上钯催化的咪唑直接芳基化的深入机理研究。已详细研究了三苯基膦(PPh 3)连接的芳基-Pd与1,2-二甲基-1 H-咪唑(dmim)的相互作用。与以前的建议相反,膦连接的有机钯物种不活跃,反应通过咪唑连接的有机钯中间体进行。在Pd(dba)2 / dmim模型系统中已表征了具有dmim连接的Pd(0)物种的芳基卤化物氧化加成的动力学。涉及新颖的平衡的彻底的研究[ARPD(dmim)2 X]复合物(X = I,OAC)和意想不到的阳离子[ARPD(dmim)3 ] +也有报道。这些物种的以实现C中的能力在乙酸的存在下dmim h的芳基化在室温下也被证实。