Enantioselective Catalytic Hantzsch Dihydropyridine Synthesis

Optically enriched Hantzsch dihydropyridines bearing different ester groups were obtained through the asymmetric catalytic cascade reaction between 3-amino-2-butenoates and (Z)-2-arylidene-3-oxobutanoates. The N,N′-dioxide/NiII or NdIII complex catalysts were disclosed to be efficient, furnishing a variety of the products, including drugs like nitrendipine, nimodipine, and felodipine, in high yields (up to 99% yield) with excellent enantioselectivities (up to 99% ee). Two enantiomers of the products can be obtained readily via exchange of the ester group of the two reactants. In addition, axial chiral 4-arylpyridines were also afforded through an oxidation process.