Expeditious Synthesis of Functionalized Piperidines by Regioselective Ring Opening of Aziridines by Enals Catalyzed by an N-Heterocyclic Carbene.

Ketones of type (I), previously prepared by ring opening of aziridines with enals, undergo a regio- and diastereoselective intramolecular aza-Michael addition to afford cis-piperidinones in high yields.