The 4-cyano-substituted bicyclic compounds 10 and 11 were prepared by reaction of the aldehyde dimer 7 with a cis-trans mixture of 4-bromo crotononitrile followed by treatment with corresponding N-substituted hydroxylamines. The diastereomers 10a and 10b could be separated by flash chromatography. The key step in the synthesis of compounds 15 and 16 was the Wittig reaction of 13 with cyanomethylene triphenylphosphorane affording a mixture of diastereomers 14a and 14b, which were separated by flash chromatography. Separate Swern oxidation of 14a and 14b, followed by reaction with N-(4-tert-butylphenyl)hydroxylamine gave bicyclic compounds 15a and 15b, respectively. In the same way 16b was prepared. The action of lithium diisopropylamide on the N-aryl-substituted compounds 10b and 15b possessing an exo-hydrogen atom at 4-position converted these to the bicyclic β-lactams 18 and 19, respectively. In contrast neither diastereomers 10a and 15a with an endo-hydrogen atom, nor the N-alkyl-substituted compounds 11 or 16b, nor compounds of type 17 were affected by LDA under equal conditions.