Five-component synthesis of dihydropyridines based on diketene

A novel five-component strategy involving commercially available diketene, primary amines, malononitrile and various benzaldehydes for the synthesis of densely functionalized 1,4-dihydropyridines in good yields was achieved. The reaction pathway involves a sequential ring-opening of diketene/enamine formation/Knoevenagel-condensation/Michael addition and 6-exo-tet cyclization, resulting in multiple bond-formation events including two C-C and three C-N bonds ultimately leading to the formation of the respective 1,4-dihydropyridines.

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