Palladium-Catalyzed Direct Arylation of Pyrazole Derivatives: A Green Access to 4-Arylpyrazoles
作者:Henri Doucet、Maurice Santelli、Yacoub Fall
DOI:10.1055/s-0029-1217075
日期:2010.1
1,3,5-Trisubstituted pyrazoles were found to be suitable partners for palladium-catalyzed direct arylation via C-H activation/functionalization using aryl bromides. The reaction conditions and the catalyst have a determining influence on the yields. The system using palladium(II) acetate as the catalyst, potassium acetate as the base, and N,N-dimethylacetamide as the solvent promotes selective 4-arylations
发现1,3,5-三取代的吡唑是使用芳基溴化物通过CH活化/官能化进行钯催化的直接芳基化的合适伴侣。反应条件和催化剂对产率具有决定性的影响。使用乙酸钯(II)作为催化剂,乙酸钾作为碱,N,N-二甲基乙酰胺作为溶剂的系统以中等至高收率促进选择性4-芳基化。几种芳基和杂芳基溴化物衍生物已被成功使用。它们的电子性能对偶联产物的产率具有决定性的影响。贫电子芳基溴给出令人满意的结果,而富电子芳基溴给出较低的产率。 吡唑-钯催化-CH芳基化-芳基溴化物