Enantioselective synthesis of polysubstituted cyclopentanones by organocatalytic double Michael addition reactions.

The O-TMS-protected diphenylprolinol-catalyzed cascade double Michael addition reactions of alpha,beta-unsaturated aldehydes with a beta-keto ester bearing a highly electron-deficient olefin unit occur smoothly to afford polysubstituted cyclopentanones. This process allows formation of four contiguous stereocenters in the cyclopentanone ring in one-step with excellent enantioselectivity.