Highly Enantioselective 1,4-Addition of Diethyl Phosphite to Enones Using a Dinuclear Zn Catalyst

An experiment was conducted to show highly enantioselectivities 1,4-addition of diethyl phosphite to enones through dinuclear zinc catalyst. The use of diethylzinc in combination with chiral ligands such as amino alcohols effectively led to chiral induction for current transformation. The bifunctional catalyst, as a powerful asymmetric catalyst for several enantioselective reactions, led to the formation of a zinc phosphonate intermediate and catalyzed the asymmetric phospha-Michael addition reaction. All enones were treated under phospha-Michael addition reaction, and comparison of the reaction yields showed that enones with an ortho-substituted phenyl or a naphthyl at the βc-position exhibited a slightly reduced reactivity caused by the steric hindrance. The asymmetric synthesis of biologically active phosphonates and derivatives can be more easily accessed using proposed method.