Copper-catalyzed enantioselective conjugate addition of diethylzinc to α,β-unsaturated carbonyl compounds using diphosphonites as chiral ligands

BINOL-based diphosphonites in which ferrocene functions as the achiral backbone are excellent chiral ligands in the Cu(OTf)2-catalyzed conjugate addition of Et2Zn to enones, enantioselectivities of up to 99% being observed.