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Gold‐Catalyzed Ring Expansion of Alkynyl Heterocycles through 1,2‐Migration of an Endocyclic Carbon–Heteroatom Bond
Author(s) -
Chen Ming,
Sun Ning,
Xu Wei,
Zhao Jidong,
Wang Gaonan,
Liu Yuanhong
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201504165
Subject(s) - heteroatom , chemistry , ring (chemistry) , regioselectivity , pyridine , catalysis , nucleophile , medicinal chemistry , combinatorial chemistry , stereochemistry , organic chemistry
A mild and efficient gold‐catalyzed oxidative ring‐expansion of a series of alkynyl heterocycles using pyridine‐ N ‐oxide as the oxidant has been developed, which affords highly valuable six‐ or seven‐membered heterocycles with wide functional group toleration. The reaction consists of a regioselective oxidation and a chemoselective migration of an endocyclic carbon–heteroatom bond (favored over CH migration) with the order of migratory aptitude for carbon–heteroatom bonds being CS>CN>CO. In the absence of an oxidant, polycyclic products are readily constructed through a ring‐expansion/Nazarov cyclization reaction sequence.