Organocatalytic Michael Addition of Aldehydes to γ-Keto-α,β-unsaturated Esters. An Efficient Entry to Versatile Chiral Building Blocks

The diarylprolinol ether/HOAc-catalyzed Michael addition of aldehydes to gamma-keto-alpha,beta-unsaturated esters occurs in a highly regioselective and enantioselective manner. The adducts could easily be converted into synthetically useful cyclohexenones, cyclohexanones, piperidines, and gamma-lactones.