Regioselective synthesis of 2(1H)-pyridinones from β-aminoenones and malononitrile.: Reaction mechanism

The identification of some intermediates of the reactions between beta-aminoenones and malononitrile to give 2(1H)-pyridinones has allowed us to obtain valuable information concerning its mechanism. These reactions begin with a conjugated addition of the nitrile to the enone followed by elimination. The compounds thus obtained cyclize to nonisolable 2H-pyran-2-imine. This afforded 2(1H)-pyridinones by ring opening to unsaturated aminoamides followed by cyclization (Dimroth-type rearrangement).