Organocatalytic Asymmetric Michael-Type/Wittig Reaction of Phosphorus Ylides: Synthesis of Chiral α-Methylene-δ-Ketoesters

  • 10.1021/ol201483s
  • Org. Lett.
  • p 4-1, 13 (16), Issue 16,
  • Letter
An asymmetric Michael-type reaction of phosphorus ylides and α,β-unsaturated ketones under the catalysis of a chiral ion pair catalyst has been described. The ion pair catalyst containing a chiral counteranion was prepared by simply mixing 9-amino-(9-deoxy)-epi-quinine with l-N-Boc-proline. The optically active α-methylene-δ-ketoesters could be obtained with good to excellent enantioselectivities (up to 95% ee) under mild reaction conditions.