Direct Arylation of Simple Azoles Catalyzed by 1,10-Phenanthroline Containing Palladium Complexes: An Investigation of C4 Arylation of Azoles and the Synthesis of Triarylated Azoles by Sequential Arylation
作者:Fumitoshi Shibahara、Eiji Yamaguchi、Toshiaki Murai
DOI:10.1021/jo200067y
日期:2011.4.15
amounts of azoles, selective C5 monoarylation was achieved by using the same catalytic system. Subsequent efforts demonstrated that C5 arylated azoles undergo exclusive C2 arylation using [Pd(phen)2]PF6 as the catalyst with galvinoxyl as an additive. Finally, unprecedented C4 arylation reactions of 2,5-diaryl-azoles occur by using the new catalytic system to give the corresponding triarylated products in
描述了由[Pd(phen)2 ] PF 6催化的简单唑的直接三芳基化和顺序三芳基化反应。在[Pd(phen)2 ] PF 6作为催化剂和化学计量的存在下,当使用芳基碘化物处理时,即使是简单的唑类,例如N-甲基咪唑,噻唑和恶唑,即使在其C4位上也发生三芳基化反应。150°C下DMA中Cs 2 CO 3的摩尔数。使用过量的唑类,使用相同的催化系统可实现选择性的C5单芳基化。随后的研究表明,C5芳基化的吡咯使用[Pd(phen)2 ] PF 6进行排他的C2芳基化作为催化剂,加尔维诺尔为添加剂。最后,通过使用新的催化体系,发生了前所未有的2,5-二芳基-唑的C4芳基化反应,从而以良好或优异的收率得到了相应的三芳基化产物。机理研究的结果表明,芳基化C2过程由电芳族取代(S的方式发生ë AR)palladation通路,而在C4位的芳基化反应经由A S发生ë氩palladation和/或自由基机理。