Highly regioselective synthesis of cis-β-enaminones by 1,4-addition of propiolaldehydes

A convenient one-pot strategy for the regioselective synthesis of cis-β-enaminones has been developed via the condensation of propiolaldehydes and amines in EtOH. This process has opened a new synthetic route to enamines in good yield. A possible reaction mechanism involving a Michael addition/enol tautomerization via a six-membered ring transition state is proposed.