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N‐Heterocyclic‐Carbene‐Catalyzed Umpolung of Imines
Author(s) -
Patra Atanu,
Mukherjee Subrata,
Das Tamal Kanti,
Jain Shailja,
Gonnade Rajesh G.,
Biju Akkattu T.
Publication year - 2017
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201611268
Subject(s) - umpolung , aldimine , carbene , chemistry , organocatalysis , catalysis , intramolecular force , tautomer , medicinal chemistry , combinatorial chemistry , organic chemistry , stereochemistry , enantioselective synthesis , nucleophile
Abstract N‐Heterocyclic carbene (NHC) catalysis has been widely used for the umpolung of aldehydes, and recently for the umpolung of Michael acceptors. Described herein is the umpolung of aldimines catalyzed by NHCs, and the reaction likely proceeds via aza‐Breslow intermediates. The NHC‐catalyzed intramolecular cyclization of aldimines bearing a Michael acceptor resulted in the formation of biologically important 2‐(hetero)aryl indole 3‐acetic‐acid derivatives in moderate to good yields. The carbene generated from the bicyclic triazolium salt was found to be efficient for this transformation.