Highly enantioselective 1,4-addition of diethyl phosphite to enones using a dinuclear Zn catalyst.

Zinc benefits: The first catalytic asymmetric phospha-Michael addition of enones has been developed. Under mild reaction conditions, the gamma-oxo phosphonates could be obtained in high yields (up to 99%) with excellent enantioselectivities (93-99% ee; see scheme). The strategy makes the asymmetric synthesis of biologically important phosphonate compounds more accessible.