Regiocontrolled Synthesis of 1,2-Diaryl-1H-imidazoles by Palladium- and Copper-Mediated Direct Coupling of 1-Aryl-1H-imidazoles with Aryl Halides under Ligandless Conditions
作者:Fabio Bellina、Silvia Cauteruccio、Luisa Mannina、Renzo Rossi、Stéphane Viel
DOI:10.1002/ejoc.200500636
日期:2006.2
involving the formation of an organocopper(I) derivatives followed by a transmetallation reaction with an arylpalladium(II) halide species and a reductive elimination, is proposed. New one-step procedures for the synthesis of 1,2,5-triaryl-1H-imidazoles, based on palladium- and copper-mediated arylation of 1-aryl-1H-imidazoles, have also been developed. Interestingly, some imidazole derivatives prepared in
通过在 DMF 中将 1-芳基-1H-咪唑与芳基碘化物或溴化物直接偶联,以中等至高产率区域选择性地合成了多种 1,2-二芳基-1H-咪唑,包括选择性 COX-2 抑制剂。在无配体条件下存在 CsF 和催化量的 Pd(OAc)2。提出了这种新的高区域选择性 C-2 芳基化反应的可能机制,包括形成有机铜 (I) 衍生物,然后与芳基钯 (II) 卤化物物种进行金属转移反应和还原消除。还开发了基于钯和铜介导的 1-芳基-1H-咪唑芳基化的新一步法合成 1,2,5-三芳基-1H-咪唑。有趣的是,已发现本研究中制备的某些咪唑衍生物对某些人类肿瘤细胞系具有显着的细胞毒活性。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)