Palladium/Norbornene‐Catalyzed C−H Alkylation/Alkyne Insertion/Indole Dearomatization Domino Reaction: Assembly of Spiroindolenine‐Containing Pentacyclic Frameworks

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...

Full description

Saved in:
Bibliographic Details
Published in:Angewandte Chemie International Edition 2018-04, Vol.57 (18), p.5151-5155
Main Authors: Bai, Lu, Liu, Jingjing, Hu, Wenjie, Li, Kunyu, Wang, Yaoyu, Luan, Xinjun
Format: Article
Language:English
Subjects:
Alkylation
Alkynes
Cascade chemical reactions
Catalysis
Chemical reactions
cyclizations
C−H activation
dearomatization
heterocycles
Hydrogen bonds
Indoles
Insertion
Molecular chains
Organic chemistry
Palladium
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary: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. A sequence of three: A novel palladium/norbornene (NBE) catalyzed intermolecular annulation of indole‐derived aryl iodides with tethered bromoalkyl alkynes has been developed for the rapid construction of pentacyclic scaffolds containing a spiroindolenine fragment. This reaction was realized through a C−H alkylation, alkyne insertion, and indole dearomatization sequence.
ISSN:1433-7851
1521-3773
DOI:10.1002/anie.201801894