Palladium/Norbornene‐Catalyzed C−H Alkylation/Alkyne Insertion/Indole Dearomatization Domino Reaction: Assembly of Spiroindolenine‐Containing Pentacyclic Frameworks |
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| Authors: | Lu Bai Jingjing Liu Wenjie Hu Kunyu Li Prof. Dr. Yaoyu Wang Prof. Dr. Xinjun Luan |
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| Affiliation: | 1. Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, College of Chemistry & Materials Science, Northwest University, Xi'an, China;2. State Key Laboratory of Elemento-organic Chemistry, Nankai University, Tianjin, China |
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| Abstract: | 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(sp2)?C(sp3) and one C(sp2)?C(sp2) 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. |
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| Keywords: | C− H activation cyclizations dearomatization heterocycles palladium |
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