Synthetic Organic Chemistry Research Laboratory, Department of Chemistry, University of Delhi, Delhi 110007, India.
J Org Chem. 2020 Nov 6;85(21):13983-13996. doi: 10.1021/acs.joc.0c02024. Epub 2020 Oct 16.
A series of palladium N-heterocyclic carbene (NHC) complexes of type -{(NHC)PdClL} (L = CHN, 3-ClCHN, and PPh) (-) have been developed as efficient precatalysts for direct C-H bond arylation of various heteroarenes. In particular, an in situ generated new NHC ligand derived from {1,3-di-(2,6-diethylphenyl)acenaphtho[1,2-] imidazolium} chloride () is used for the stabilization of the palladium metal center. Among the screened palladium precatalysts (-), the most active PEPPSI themed complex () was successfully employed toward direct C-H bond arylation of various heteroarenes and aryl bromides. A range of functional groups on aryl bromides as well as on heteroarenes sustained throughout the standard reaction conditions for easy access of various arylated heterocyclic compounds. Significantly, the utility of the protocol was demonstrated by the effective synthesis of a precursor of raloxifene, a selective estrogen receptor modulator.
已经开发出一系列钯氮杂环卡宾（NHC）配合物，其类型为{-（NHC）PdClL}（L = CHN、3-ClCHN 和 PPh）（-），它们是各种杂芳烃直接 C-H 键芳基化的有效前催化剂。特别是，从{1,3-二-（2,6-二乙基苯基）吖[1,2-]咪唑啉𬭩}氯化物（）原位生成的新 NHC 配体用于稳定钯金属中心。在所筛选的钯前催化剂（-）中，最活跃的 PEPPSI 主题配合物（）成功地用于各种杂芳烃和芳基溴化物的直接 C-H 键芳基化。芳基溴化物和杂芳烃上的各种官能团在标准反应条件下都能得到维持，从而容易获得各种芳基杂环化合物。重要的是，该方案的实用性通过有效合成选择性雌激素受体调节剂雷洛昔芬的前体得到了证明。
