Liu Zheng, Li Qian, Yang Chengyong, Zheng Xuesong, Wu Di, Gao Ge, Lan Jingbo
Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, P. R. China.
Chem Commun (Camb). 2022 Jun 21;58(50):7042-7045. doi: 10.1039/d2cc01646j.
Herein, N-heterocyclic carbene-directed Ir(III)-catalyzed cascade C-H arylation/annulation of -arylimidazolium with diaryliodonium salts has been accomplished for the first time a quadruple C-H activation strategy to construct imidazo[1,2-]phenanthridinium structures. This protocol overcomes the compatibility of three kinds of different C-H activations with high catalytic efficiency, which allows -unhindered -arylimidazoliums to undergo a diarylation/annulation reaction, affording a variety of polysubstituted imidazo[1,2-]phenanthridiniums. Neutral imidazo[1,2-]phenanthridines are also prepared a demethylation reaction of imidazo[1,2-]phenanthridiniums.
在此，首次实现了氮杂环卡宾导向的铱（III）催化的α-芳基咪唑鎓与二芳基碘鎓盐的级联C-H芳基化/环化反应，这是一种构建咪唑并[1,2-a]菲啶鎓结构的四重C-H活化策略。该方案以高催化效率克服了三种不同C-H活化反应的兼容性问题，使得未受阻的α-芳基咪唑鎓能够进行双芳基化/环化反应，得到多种多取代的咪唑并[1,2-a]菲啶鎓。中性的咪唑并[1,2-a]菲啶也可通过咪唑并[1,2-a]菲啶鎓的去甲基化反应制备。
