l-Proline-catalyzed synthesis of highly functionalized multisubstituted 1,4-dihydropyridines

Abstract

Highly functionalized multisubstituted 1,4-dihydropyridines 5 have been concisely synthesized in moderate to good yields viaL-proline-catalyzed one-pot multicomponent reactions (MCRs) of alkynoates or alkynones 1, amines 2, β-dicarbonyl compounds 3 and aldehydes 4 under mild conditions. The MCR process involves hydroamination/Knoevenagel condensation/Michael-type addition/intramolecular cyclization processes and leads to the formation of 1,4-dihydropyridines 5. The molecular structure of 5ckaa was confirmed by single-crystal X-ray diffraction. This method is energy saving and environmentally friendly, providing easy access to diverse multisubstituted polyfunctional 1,4-dihydropyridines.