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Gold‐Catalyzed Oxidative Ring Expansion of 2‐Alkynyl‐1,2‐Dihydropyridines or ‐quinolines: Highly Efficient Synthesis of Functionalized Azepine or Benzazepine Scaffolds
Author(s) -
Chen Ming,
Chen Yifeng,
Sun Ning,
Zhao Jidong,
Liu Yuanhong,
Li Yuxue
Publication year - 2015
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201410056
Subject(s) - azepine , benzazepine , chemistry , ring (chemistry) , catalysis , combinatorial chemistry , benzazepines , oxidative phosphorylation , medicinal chemistry , organic chemistry , biochemistry
A gold‐catalyzed highly regio‐ and chemoselective oxidative ring expansion of 2‐alkynyl‐1,2‐dihydropyridines and its analogues using pyridine‐N‐oxide as the oxidant has been developed. Ring expansion proceeds through exclusive 1,2‐migration of a vinyl or phenyl group, whereas no 1,2‐H and 1,2‐N migration take place. The reaction provides an efficient and attractive route to various types of medium‐sized azepine derivatives in generally high to excellent yields with a broad functional group tolerance. DFT studies indicate that the reaction proceeds through the formation of a cyclopropyl gold intermediate, and no gold carbene species is involved.