Synergistic effect of achiral quaternary ammonium salt on asymmetric additions of diethylzinc to aldehydes

Our investigation has shown that achiral quaternary ammonium salt has a significant synergistic effect on the asymmetric additions of diethylzinc to aldehydes catalyzed by chiral phosphoramide–Zn(II) complex. The addition of 10 mol % NBu4X can dramatically reduce the loading amount of chiral ligand without sacrificing the excellent reactivity and enantioselectivity of the asymmetric reaction.