Palladium Complexes of Thio/Seleno‐Ether Containing
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‐Heterocyclic Carbenes: Efficient and Reusable Catalyst for Regioselective C‐H Bond Arylation
作者:Ramprasad Bhatt、Nattamai Bhuvanesh、Kamal Nayan Sharma、Hemant Joshi
DOI:10.1002/ejic.201901259
日期:2020.2.14
C1–C3 have been explored in the catalysis of C–H bond arylation of imidazoles. The protocol operates under mild reaction conditions in air with an excellent regioselective C–H bond arylation at C‐5 position in imidazoles. All the complexes were found to be efficient (yield up to 97 % in 12 h) in the catalysis; however, the activating pincer ligand framework containing Pd catalyst C3, was found to be utmost
本文使用1-(2-((苯硫基)乙基)-1H-咪唑与苄基溴和溴代二苯甲烷的原子经济反应描述了新型S,C NHC型半钳位配体前体(L1和L2)的合成, 分别。1-(2-(苯基硒基乙基)乙基)-1H-咪唑与2-溴乙基苯基硫化物的类似反应也产生了溴化咪唑鎓(L3),这是新型S,C NHC,Se型钳位配体的前体。采用银-NHC的金属转移途径得到钯络合物[Pd(L1 / L2 -HBr)Cl 2 ](C1和C2)和[Pd(L3- HBr)Cl] BF 4(C3)。使用多核NMR和HR-MS对溴化咪唑鎓(L1 - L3)和钯配合物(C1 - C3)进行了表征。X射线晶体学验证了配合物C1和C2中的结构和键合。具有热稳定性且对湿气/空气不敏感的钯配合物C1 - C3已在咪唑的C–H键芳基化催化中进行了探索。该方案在空气中温和的反应条件下运行,在咪唑的C-5位置具有出色的区域选择性C–H键芳基化。发现所有的