Enantioselective organocatalytic Michael additions of aldehydes to enones with imidazolidinones: cocatalyst effects and evidence for an enamine intermediate.
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.
Peelen
Timothy J
TJ
Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, USA.
Chi
Yonggui
Y
Gellman
Samuel H
SH
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
D000447:Aldehydes; D000588:Amines; D048289:Imidazolidines; D007659:Ketones; D009942:Organometallic Compounds