Enamides: Occurrence, importance, synthetic methods and applications

Enamides constitute an important class of synthetic intermediates, as well as form structural component of many bioactive natural products. Enamides because of their high reactivity comprise an important class of functional group for the preparation of heterocyclic compounds. Another important feature of enamides which makes them important scaffolds in organic synthesis and medicinal chemistry is the balance between stability and reactivity. Enamides are treated as the electron-deficient enamines consisting of alkene substituted by nitrogen functionality like imidazolidinone, lactam, oxazolidinone or amide. In case of the cyclic enamides, the enamide double bond is constrained within a heterocycle, however, the _-substituted enamides with alkenyl side chain on the nitrogen exist as configurational isomers.