N-Heterocyclic Carbenes Catalyzed Umpolung Reactions via Homoenolates
نویسندگان
چکیده
منابع مشابه
Formal Diels-Alder reactions of chalcones and formylcyclopropanes catalyzed by chiral N-heterocyclic carbenes.
Highly enantioselective (formal) hetero-Diels-Alder reactions between chalcones and formylcyclopropanes are disclosed. The challenging N-heterocyclic carbene (NHC)-bounded enolate intermediates from formylcyclopropanes were captured for new C-C bond forming reactions. The reaction products were obtained with high diastereo- and enantioselectivities and could be easily transformed to optically p...
متن کاملN-Heterocyclic carbenes
The N-heterocyclic carbenes (NHC) now hold a preferredligand status in organic and organometallic chemistry. Their role in catalysis continues to grow. When the editorial staff at the Beilstein Journal of Organic Chemistry contacted me to act as a guest editor for the thematic series “N-Heterocyclic carbenes”, I was more than happy to accept what appeared to me to be a simple and exciting endea...
متن کاملEnantioselective Stetter reactions of enals and modified chalcones catalyzed by N-heterocyclic carbenes.
Organocatalytic activation of readily available substrates has led to the rapid development of many enantioselective reactions in the last decade. In N-heterocyclic carbene (NHC) catalysis, reactions of enals with enones or enone derivatives have been extensively investigated and are reported to undergo a diverse set of transformations based on the catalytically generated enolate and homoenolat...
متن کاملEnantioselective Diels-Alder reactions of enals and alkylidene diketones catalyzed by N-heterocyclic carbenes.
An electron-withdrawing group was introduced to the α-position of chalcones, and the resulting alkylidene diketones showed new reactivities with enals under the catalysis of N-heterocyclic carbenes (NHCs). Selective activation of enals affords enolate equivalents that undergo highly enantioselective intermolecular Diels-Alder reactions with the alkylidene diketones. No products that might have ...
متن کاملOrganocatalysis by N-heterocyclic carbenes.
In the investigation of efficient chemical transformations, the carbon-carbon bond-forming reactions play an outstanding role. In this context, organocatalytic processes have achieved considerable attention.1 Beside their facile reaction course, selectivity, and environmental friendliness, new synthetic strategies are made possible. Particularly, the inversion of the classical reactivity (Umpol...
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ژورنال
عنوان ژورنال: Journal of Synthetic Organic Chemistry, Japan
سال: 2007
ISSN: 0037-9980,1883-6526
DOI: 10.5059/yukigoseikyokaishi.65.1009