A common thread that runs through these NHC catalyzed reactions is the proposed involvement of an enaminol, also known as the Breslow intermediate, formed by the nucleophilic addition of an NHC to a carbonyl group of a suitable electrophile.

2022年3月3日 · Under aprotic conditions, the stoichiometric reaction of N-heterocyclic carbenes (NHCs) such as imidazolidin-2-ylidenes with aldehydes affords Breslow Intermediates (BIs), involving a formal 1,2-C-to-O proton shift.

2021年5月11日 · A common thread that runs through these NHC catalyzed reactions is the proposed involvement of an enaminol, also known as the Breslow intermediate, formed by the nucleophilic addition of an NHC to a carbonyl group of a suitable electrophile.

2021年11月29日 · Breslow intermediate (BI) derived from a thiazolin-2-ylidene, i.e., the arom. heterocycle present in vitamin B1, is reported. Key to success was the combined use of pentafluorobenzaldehyde and a thiazolin-2-ylidene carrying an enol-stabilizing dispersion energy donor as N-substituent.

2021年2月5日 · Breslow intermediates (BIs) are the crucial nucleophilic amino enol intermediates formed from electrophilic aldehydes in the course of N-heterocyclic carbene (NHC)-catalyzed umpolung reactions.

2022年1月14日 · The mechanism of formation of the Breslow intermediate (BI) under aprotic conditions is investigated with density functional theory (DFT) calculations. The zwitterionic adduct (ZA) is formed by the first addition of an imidazolinylidene to benzaldehyde.

2020年9月7日 · Abstract: Breslow intermediates (BIs) are the crucial nucleo-philic amino enol intermediates formed from electrophilic al-dehydes in the course of N-heterocyclic carbene (NHC)-cata-lyzed umpolung reactions.

2012年3月28日 · Herein, we report the isolation and full characterization of nitrogen analogues of the Breslow intermediate. Both stable and catalytically relevant, these species provide a model system for the study of acyl carbanion and homoenolate processes catalyzed by …

2012年10月29日 · A 54-year quest for carbene chemists just took a big step toward resolution: German researchers say they’ve generated and characterized elusive Breslow intermediates, which are crucial players in biochemistry and catalysis (Angew. Chem. Int. Ed., DOI: 10.1002/anie.201205878).

2021年6月17日 · In summary, Breslow intermediates arising from mesoionic carbenes act as super electron donors in catalytic cycles that engage iodoarenes in arylacylation reactions of alkenes. This paper should herald a range of new reactions based on …