Asymmetric Anion-π Catalysis: Enamine Addition to Nitroolefins on π-Acidic Surfaces
Yingjie Zhao1, Yoann Cotelle1, Alyssa-Jennifer Avestro1,2
1Department of Organic Chemistry, University of Geneva , Geneva CH-1211, Switzerland.
Abstract:
Here we provide experimental evidence for anion-π catalysis of enamine chemistry and for asymmetric anion-π catalysis. A proline for enamine formation on one side and a glutamic acid for nitronate protonation on the other side are placed to make the enamine addition to nitroolefins occur on the aromatic surface of π-acidic naphthalenediimides. With increasing π acidity of the formally trifunctional catalysts, rate and enantioselectivity of the reaction increase. Mismatched and more flexible controls reveal that the importance of rigidified, precisely sculpted architectures increases with increasing π acidity as well. The absolute configuration of stereogenic sulfoxide acceptors at the edge of the π-acidic surface has a profound influence on asymmetric anion-π catalysis and, if perfectly matched, affords the highest enantio- and diastereoselectivity.
Related Concept Videos
Nitrosation of Enols
α-Alkylation of Ketones via Enolate Ions
Aldehydes and Ketones with Amines: Enamine Formation Mechanism
Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
Conjugate Addition of Enolates: Michael Addition
Synthesis of α-Substituted Carbonyl Compounds: The Stork Enamine Reaction


