title: Enantioselective organocatalytic Michael additions of aldehydes to enones with imidazolidinones: cocatalyst effects and evidence for an enamine intermediate.
abstract: An enantioselective intermolecular Michael addition of aldehydes to enones catalyzed by imidazolidinones has been achieved. Chemoselectivity (Michael addition vs aldol) can be controlled through judicious choice of hydrogen-bond-donating cocatalysts. The optimal imidazolidinone/hydrogen-bond-donor pair affords Michael addition products in excess of 90% ee. Furthermore, we have isolated and characterized an enamine intermediate and demonstrated its efficacy as a nucleophile in the observed Michael addition reactions.
authors.affiliation: Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, USA.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Peelen
authors.forename: Yonggui
authors.initials: Y
authors.lastname: Chi
authors.forename: Samuel H
authors.initials: SH
authors.lastname: Gellman
mesh_terms: D000447:Aldehydes / Q000138:chemical synthesis* / Q000737:chemistry; D000588:Amines / Q000737:chemistry*; D002384:Catalysis; D006860:Hydrogen Bonding; D048289:Imidazolidines / Q000138:chemical synthesis* / Q000737:chemistry; D007659:Ketones / Q000138:chemical synthesis* / Q000737:chemistry; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000447:Aldehydes; D000588:Amines; D048289:Imidazolidines; D007659:Ketones; D009942:Organometallic Compounds