Diels-alder cycloadditions of diene-substituted N-ethoxycarbonyl-2-methyl-1,2-dihydropyridines with N-phenylmaleimide

The ten possible substitution patterns for N-Ethoxycarbonyl-2-methyl-1,2-dihydropyridines 5 in which one or two olefinic sites are alkyl substituted were synthesized and reacted with N-phenylmaleimide 2 to provide cycloadducts 6. N-Ethoxycarbonyl-5,6-cyclohexyl-2-methyl-1,2-dihydropyridine 51 provided the novel spirocycle 61.