Photolysis and cycloaddition reactivity of diferrocenyl substituted cyclopentadienone

The photolysis results of new diferrocenyl substituted cyclopentadienone(3) show that sunlight and air play an important role in the decomposition of compound 3, and two new compounds, 2-cyclopentenone(4) and α-pyrone(5), were obtained viaphotolysis of compound 3. The photolysis process was investigated by 1H NMR, and a plausible mechanism for the formation of compound 5was deduced. The cycloaddition reactions of substituted cyclopentadienones(3, 7, 9) with maleimide gave substituted imides 8, 10, 11, 12and an unprecedented diferrocenyl substituted 1H-pyrrol-3(2H)-one derivative 13, respectively. The structures of compounds 4, 5, 8, 10, 11, 12and 13were confirmed by X-ray single crystal diffraction analysis technique.