The three-component reactions of aromatic aldehydes, arylamines, and acetylenedicarboxylates show very interesting molecular diversity. In an aqueous ethanol solution the threecomponent reaction gave polysubstituted 2-hydroxyhydropyridines. In absolute ethanol 1,4-dihydropyridines were

A practical and efficient procedure for the preparation of the polysubstituted dihydropyridines was developed through a unique four-component reaction of aromatic aldehydes, malononitrile, arylamines, and acetylenedicarboxylate in ethanol in the presence of triethylamine as a base promoter. This four-component reaction is atom-efficient, high-yielding, and applicable to a wide variety of four-component reactions.

The domino reactions of 1,3-thiazolidinedione, malononitrile, and aromatic aldehydes in the presence of different organic amines were studied. Secondary amines such as pyrrolidine, piperidine, morpholine, and dimethylamine and primary amines such as benzylamine yield dihydrothiophene derivatives through a domino ring-opening/recyclization reaction of 1,3-thiazolidinedione. Bulky diethylamine, diisopropylamine, and 1,4-diazabicyclo[2.2.2]octane give spirocyclohexano-1,3-thiazole through a double Michael addition/spirocyclization reaction.

In the presence of triethylamine as base catalyst, aromatic amines have successfully been used as substrates in the domino reactions of 1,3‐thiazolidinedione, malononitrile, and aromatic aldehydes. Through a domino ring‐opening/recyclization process of 1,3‐thiazolidinedione, a series of polysubstituted dihydrothiophenes in the trans configuration have been synthesized in high yields. Dihydrothiophene derivatives can be converted efficiently into the corresponding thiophenes by oxidation with DDQ under mild conditions.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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.