Phosphine-free palladium-catalysed direct C2-arylation of benzothiophenes with aryl bromides
作者:Liqin Zhao、Christian Bruneau、Henri Doucet
DOI:10.1016/j.tet.2013.06.037
日期:2013.8
some electron-rich aryl bromides. The presence of a methyl or a formyl substituent at C3 of benzothiophene has a minor influence on the reactivity, and even a bromo substituents at C3 is tolerated. A wide variety of functional groups on the aryl bromide, such as nitrile, nitro, acetyl, formyl, ester, chloro, fluoro or trifluoromethyl has been employed.
发现无配体的Pd(OAc)2在低催化剂浓度下非常有效地催化苯并噻吩衍生物的直接C2-芳基化。该反应可使用少至0.5-0.1 mol%的催化剂,具有缺电子和一些富电子的芳基溴化物来进行。苯并噻吩的C3处甲基或甲酰基取代基的存在对反应性的影响很小,甚至C3处的溴取代基也是可以容忍的。已经使用了芳基溴上的各种官能团,例如腈,硝基,乙酰基,甲酰基,酯,氯,氟或三氟甲基。