Stereoselective synthesis of tricyclic derivatives of 2-amino-1-pyrrolin-5-one dimethyl acetals

Reactions of a tetracyanobicycloalkene (1) with methanol and ethylene glycol give derivatives of 2-aminopyrrolin-5-one (2 and 3), and acid hydrolysis of3 gives an imide (4). According to an X-ray structural investigation, acis orientation of the heterocycle (with respect to the C=C bond) is realized in2; in the case of4, thecis/trans ratio of the isomers in the crystal and solution is 2∶1.