Nitroketeneaminals, XI: Reaction of enones wit N,N'-cyclically alkylated nitroketeneaminals

Article abstract of DOI:10.1002/ardp.19933260606

Reaction of enones 2a-d with nitroketeneaminals 3, 4, and 5 in refluxing ethanol yields the Michael adduct 8a and the bicyclic carbinolamines 9, 10, and 11. Dehydratisation of 9a-d in acidic medium leads to heteroanellated 1,4-dihydropyridines 12a-d. By means of ¹H-NMR-data the relative configuration of 10d is determined.