C−H Arylation of Thiophenes with Aryl Bromides by a Parts-per-Million Loading of a Palladium NNC-Pincer Complex
作者:Yasuhiro Uozumi、Anggi Eka Purta、Shun Ichii、Aya Tazawa
DOI:10.1055/s-0040-1707213
日期:2020.10
A palladium NNC-pincer complex efficiently catalyzed the direct arylation of thiophene derivatives with extremely low palladium loadings of the order of parts per million. Thus, the reaction of various thiophenes with aryl bromides in the presence of 25–100 mol ppm of chlorido[(2-phenyl-κ-C 2)-9-phenyl-1,10-phenanthroline-κ2-N,N′]palladium(II) NNC-pincer complex, K2CO3, and pivalic acid in N,N-dimethylacetamide
钯 NNC-钳形复合物有效催化噻吩衍生物的直接芳基化,钯负载量极低,约为百万分之几。因此,各种噻吩与芳基溴化物在 25–100 mol ppm 氯[(2-苯基-κ-C 2)-9-苯基-1,10-菲咯啉-κ2-N,N'] 存在下的反应钯 (II) NNC-钳形复合物、K2CO3 和新戊酸在 N,N-二甲基乙酰胺中提供相应的 2-或 5-芳基化噻吩,产率良好至极好。目前的 C-H 芳基化和 Hiyama 偶联与相同的 NNC 钳络合物的组合提供了不对称 2,5-噻吩的有效合成,催化剂负载量为 mol ppm 水平。