Direct C5-Arylation Reaction between Imidazoles and Aryl Chlorides Catalyzed by Palladium Complexes with Phosphines and N-Heterocyclic Carbenes
作者:P. Vijaya Kumar、Wu-Shien Lin、Jiun-Shian Shen、Debkumar Nandi、Hon Man Lee
DOI:10.1021/om200490k
日期:2011.10.10
Palladium(II) acetate complexes bearing phosphines and carbene ligands, Pd(L)(PR3)(OAc)2 (1a, R = Ph; 1b, R = Cy; L = 1,3-dibenzylimidazol-2-ylidene), were prepared by salt metathesis reactions of their chloro complexes with AgOAc in good yields. The electron-rich 1b was efficient in catalyzing C-5 direct arylation of imidazoles with aryl halides. Most significantly, the catalytic system allows a range
带有膦和卡宾配体的钯钯(II)配合物Pd(L)(PR 3)(OAc)2(1a,R = Ph; 1b,R = Cy; L = 1,3-二苄基咪唑-2-亚烷基),通过氯络合物与AgOAc的盐复分解反应以高收率制备了这些化合物。富电子1b在催化咪唑与芳基卤化物的C-5直接芳基化方面非常有效。最重要的是,催化系统允许使用多种芳基氯作为底物。微波辐射可有效促进反应,仅2小时即可获得良好的收率。结合经典的C–C键形成反应方法,成功地从1,4-二氯苯和1-溴-4-氯苯中获得了具有联芳基和苯乙烯基亚基的新型咪唑衍生物。