Asymmetric Anion-π Catalysis: Enamine Addition to Nitroolefins on π-Acidic Surfaces.
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.
Department of Organic Chemistry, University of Geneva , Geneva CH-1211, Switzerland.
Yingjie
Y
Zhao
Department of Organic Chemistry, University of Geneva , Geneva CH-1211, Switzerland.
Yoann
Y
Cotelle
Department of Organic Chemistry, University of Geneva , Geneva CH-1211, Switzerland.|Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States.
Alyssa-Jennifer
AJ
Avestro
Department of Organic Chemistry, University of Geneva , Geneva CH-1211, Switzerland.
Naomi
N
Sakai
Department of Organic Chemistry, University of Geneva , Geneva CH-1211, Switzerland.
Stefan
S
Matile
D000475:Alkenes / Q000737:chemistry*; D000588:Amines / Q000737:chemistry*; D000838:Anions; D002384:Catalysis; D006863:Hydrogen-Ion Concentration; D009574:Nitro Compounds / Q000737:chemistry*; D013237:Stereoisomerism; D013499:Surface Properties
D000475:Alkenes; D000588:Amines; D000838:Anions; D009574:Nitro Compounds