Zur Reaktivität des neuen Codimeren aus Malonitril und Cyanessigester bzw. dimeren Cyanessigester gegenüber Benzilen

Condensation of benzils with 3-amino-2,4-dicyano-crotonic-ester (2a, b) and dimer cyanoacetate (2c, d) resp. leads to 4,5-diaryl-3-pyrroline-2-ylidenecyanoacetates3a-m. It can be shown by¹³C-spectroscopy that in the monosubstituted benzil1c the carbonyl function adjacent to the unsubstituted phenyl reacts with the methylene group of2a orb. With aqueous alkaline the pyrrolines3 rearrange to pyrrolidinones4a-i.¹H-NMR-CIDNP experiments support the assumption of a partial radical character of this rearrangement.