Strontium-Catalyzed Highly Enantioselective Michael Additions of Malonates to Enones

A novel catalyst system based on a chiral strontium complex which promotes the catalytic asymmetric Michael addition reactions of malonates to enones has been developed. The conjugate addition reactions proceeded smoothly in the presence of 5 mol % of the chiral strontium catalyst, at room temperature, to afford the desired adducts in high yields and excellent enantioselectivities. This method provides an efficient approach to the preparation of building blocks possessing various functional groups and possible sites for further functionalization.