Reversal of Stereoselectivity in the Cu-Catalyzed Conjugate Addition Reaction of Dialkylzinc to Cyclic Enone in the Presence of a Chiral Azolium Compound
Reversal of enantioselectivity in a Cu-catalyzedasymmetricconjugateaddition reaction of dialkylzinc to cyclicenone with use of the same chiral ligand was successfully achieved. The reaction of 2-cyclohexen-1-one (30) with Et2Zn catalyzed by Cu(OTf)2 in the presence of an azolium salt derived from a chiral β-amino alcohol gave (S)-3-ethylcyclohexanone (31) in good enantioselectivity. Among a series