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Updated: Sep 23, 2025

A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species
Published on: August 16, 2018
N-Heterocyclic Carbene (NHC)-Catalyzed Transformations Involving Azolium Enolates
Santigopal Mondal1, Arghya Ghosh1, Akkattu T Biju1
1Department of Organic Chemistry, Indian Institute of Science, Bangalore, 560012.
Abstract:
The recent advances in the N-heterocyclic carbene (NHC)-organocatalyzed generation of azolium enolate intermediates and their subsequent interception with electrophiles are highlighted. The NHC-bound azolium intermediates are generated by the addition of NHCs to suitably substituted aldehydes, acid derivatives or ketenes. A broad range of coupling partners can intercept the azolium enolates to form [2+n] cycloadducts (n=2,3,4) and various α-functionalized compounds. The enantioselective synthesis of the target compounds are achieved with the use of chiral NHCs. Herein, we summarized the development that occurred in this subclass of NHC catalysis.
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