Asymmetric Michael reaction of an α-cyano Weinreb amide catalyzed by a rhodium complex with trans-chelating chiral diphosphine PhTRAP

Abstract

Asymmetric Michael reaction of N-methoxy- N-methyl-2-cyanopropionamide with vinyl ketones or acrolein in the presence of 0.1–1 mol% of a rhodium catalyst prepared in situ from Rh(acac)(CO) 2 and a trans-chelating chiral diphosphine ligand ( S, S)-( R, R)-PhTRAP gave optically active Michael adducts with high enantiomeric excesses (89–94%) in high yields. The adducts with methyl vinyl ketone was transformed into an α-cyano aldehyde and ketones with an quarternary asymmetric carbon center through the reaction with LiAlH 4 or Grignard reagents.