Enantioselective Cu-catalyzed 1,4-addition of Me3 Al to a 4,4-disubstituted cyclohexa-2,5-dienone

Article abstract of DOI:10.1016/0040-4020(96)00869-1

A series of chiral enantiomerically pure 2-aryloxazolines was synthesized. (4S)-2-(2',6'-dimethoxyphenyl)-4-isopropyloxazoline proved to be an efficient chiral ligand for the Cu-catalyzed conjugate addition of Me₃Al to cyclohexadienone, and by using 20 mol% of this ligand, 1,4-adduct was obtained in 68% ee. In addition, TBDMSOTf is crucial for the asymmetric conjugate addition to proceed with good chemical yield and high ee.