REGIOSELECTIVE PHOTOCHEMICAL CYCLOADDITION OF ENAMINE-CARBALDEHYDES AND ALKENES; SYNTHESIS OF 1,4-DIHYDROPYRIDINES AND 2-HYDROXY-1,2,3,4-TETRAHYDROPYRIDINES

Article abstract of DOI:10.1016/S0040-4039(00)88173-3

Photocycloaddition of enamine-carbaldehydes 1 and alkenes 2 with an electron-withdrawing or an electron-donating group 2 a-f and 2 g-h regioselectively yields the 4-substituted and the 3-substituted 2-hydroxy-1,2,3,4-tetrahydropyridines 3 respectively.Dehydratisation of 3 with electron-withdrawing groups at C-4 gives the 1,4-dihydropyridines 4.