Synthesis of Multifunctionalized 2,3-Dihydro-4-pyridones and 4‑Pyridones via the Reaction of Carbamoylated Enaminones with Aldehydes

The novel and effective diastereoselective synthesis of multifunctionalized dihydropyridones, including CF3-substituted derivatives, has been developed on the basis of the piperidine-promoted domino reaction of carbamoylated enaminones with aldehydes. The products have been prepared in 38–90% yields and can be easily isolated by crystallization. Tautomerism, epimerization, and atropisomerism of dihydropyridones have been studied. The use of the resulting dihydropyridones in the synthesis of 1,2,6-trisubstituted 4-pyridone-3-carboxamides has been demonstrated via oxidative aromatization initiated by iodine.