Enamine/Carbene Cascade Catalysis in the Diastereo- and Enantioselective Synthesis of Functionalized Cyclopentanones.

Herein we report an enantioselective synthesis of complex cyclopentanones using aliphatic aldehydes and activated enones. With the combination of a chiral secondary amine and a chiral triazolium catalyst, high diastereoselectivity and excellent enantioselectivity can be achieved. We present evidence of a clear cooperative effect when these two catalysts are present simultaneously in the system.