Direct C-H arylation of thiophenes at low catalyst loading of a phosphine-free bis(alkoxo)palladium complex.
Direct C-H arylation of thiophenes at low catalyst loading of a phosphine-free bis(alkoxo)palladium complex.
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DOI：
10.1021/jo402745b
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发表时间：
2014-03
期刊：
影响因子：
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通讯作者：
Yabo Li;Jingran Wang;Mengmeng Huang;Zhiwei Wang;Yusheng Wu;Yangjie Wu
中科院分区：
文献类型：
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作者：
Yabo Li;Jingran Wang;Mengmeng Huang;Zhiwei Wang;Yusheng Wu;Yangjie Wu
本文报道了在低催化剂负载量（Cat.I，0.1- 0.2mol%）下噻吩α位的无膦直接C-H芳基化反应。该合成方法可应用于由芳基或杂芳基溴化合物合成α-芳基/杂芳基噻吩，产率良好，且与带有给电子或吸电子基团的底物相容。噻吩的2-和5-位的反应性是等效的，并且在最佳条件下不依赖于空间位阻。该条件也可以应用于其它杂环部分，例如苯并噻吩、苯并呋喃和吡咯，具有高转化率。
An efficient phosphine-free direct C-H arylation of thiophenes at the α-position has been developed at low catalyst loading of bis(alkoxo)palladium complex (Cat.I, 0.1-0.2 mol %). The developed synthetic method can be applied to the synthesis of α-aryl/heteroaryl thiophenes from aryl or heteroaryl bromides in good to excellent yields and is compatible with the substrates bearing electron-donating or electron-withdrawing groups. The reactivities of the 2- and 5-positions of thiophenes are equivalent and not dependent on steric hindrance under optimal conditions. This condition can also be applied to other heterocyclic moieties such as benzothiophene, benzofuran, and pyrrole with high conversion yields.