A mild and efficient procedure for asymmetric Michael additions of cyclohexanone to chalcones catalyzed by an amino acid ionic liquid

A mild and efficient procedure for Michael additions of cyclohexanone to chalcones has been developed. In the presence of amino acid ionic liquid [EMIm][Pro] (200 mol %), cyclohexanone reacted with various chalcones to afford Michael adducts in high yields (85–98%) and moderate to good enantioselectivities (16–94% ee), accompanied by an unexpected solvent-dependent inversion of the enantioselectivity.

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1-Ethyl-3-methylimidazolium-(S)-2-pyrrolidinecarboxylic acid saltC11H19N3O2[α]D25=+51.0 (c 1, MeOH)Source of chirality: l-proline