Synthesis of 3,4-Dihydropyridin-2(1H)-ones and 3,4-Dihydro-2H-pyrans via Four-Component Reactions of Aromatic Aldehydes, Cyclic 1,3-Carbonyls, Arylamines, and Dimethyl Acetylenedicarboxylate

A protocol has been developed for the efficient synthesis of structurally diverse 3,4-dihydropyridin-2(1H)-ones and 3,4-dihydro-2H-pyrans via four-component reactions of arylamines, acetylenedicarboxylate, aromatic aldehydes and cyclic 1,3-diketones. The selective formation of the very different pyridinone or pyran derivatives depends on the structure of cyclic 1,3-diketone. The key steps are proposed to involve Michael addition of the enamino ester formed in situ from the reaction of arylamine with dimethyl acetylenedicarboxylate to arylidine cyclic 1,3-diketones.