Highly enantioselective and recyclable organocatalytic Michael addition of malonates to α,β-unsaturated aldehydes in aqueous media.

A new type of pyrrolidine-based organocatalyst, which was developed earlier in our lab, has been found to be very effective for the Michael addition reaction in aqueous solvents involving a wide range of α,β-unsaturated aldehydes and malonate derivatives. For the reactions studied, good to excellent yields (73%-96%) and high to excellent enantioselectivities (up to 97%) were obtained using this catalyst. In addition, the catalyst could be recycled up to four times with gradual reductions in yields and enantioselectivity observed after the second cycle.