Bai Lu, Liu Jingjing, Hu Wenjie, Li Kunyu, Wang Yaoyu, Luan Xinjun
Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, College of Chemistry & Materials Science, Northwest University, Xi'an, 710127, China.
State Key Laboratory of Elemento-organic Chemistry, Nankai University, Tianjin, 300071, China.
Angew Chem Int Ed Engl. 2018 Apr 23;57(18):5151-5155. doi: 10.1002/anie.201801894. Epub 2018 Mar 23.
Reported is a highly chemoselective intermolecular annulation of indole-based biaryls with bromoalkyl alkynes by using palladium/norbornene (Pd/NBE) cooperative catalysis. This reaction is realized through a sequence of Catellani-type C-H alkylation, alkyne insertion, and indole dearomatization, by forming two C(sp )-C(sp ) and one C(sp )-C(sp ) bonds in a single chemical operation, thus providing a diverse range of pentacyclic molecules, containing a spiroindolenine fragment, in good yields with excellent functional-group tolerance. Preliminary mechanistic studies reveal that C-H bond cleavage is likely involved in the rate-determining step, and the indole dearomatization might take place through an olefin coordination/insertion and β-hydride elimination Heck-type pathway.
报道了一种通过钯/降冰片烯（Pd/NBE）协同催化实现的吲哚基联芳基与溴代烷基炔烃的高化学选择性分子间环化反应。该反应通过一系列卡泰拉尼型C-H烷基化、炔烃插入和吲哚去芳构化反应实现，在单一化学操作中形成两个C(sp³)-C(sp²)键和一个C(sp²)-C(sp²)键，从而以良好的产率和出色的官能团耐受性提供了多种含有螺吲哚啉片段的五环分子。初步机理研究表明，C-H键裂解可能参与了速率决定步骤，吲哚去芳构化可能通过烯烃配位/插入和β-氢化物消除的Heck型途径发生。
