Structure of a Dimer Ketone Formed via Fe(CO)5-Promoted Coupling of 7-(p-Cyanophenoxy)Norbornadiene to Carbon Monoxide

摘要

As part of an ongoing study of the thermal reactions of iron carbonyls with 7-substituted norbornadienes (Marchand Hayes, 1977; Marchand, Earlywine Heeg, 1986), the reactions of Fe(CO)5 and of Fe2(CO)9 with 7-(p-cyanophenoxy)norbornadiene (1) were investigated. Compound (1) was synthesized via palladium(II)-promoted valence isomerization (Patrick Bechtold, 1984) of 3-(p-cyanophenoxy)quadricylane. Thermal reaction with Fe(CO)5, performed in refluxing di-n-butyl ether, resulted primarily in alkyl-oxygen cleavage in the substrate, thereby affording p-cyanophenol in 23% yield. The corresponding reaction with Fe2(CO)9, performed in refluxing benzene, afforded unreacted (56%), a cage dimer (2.9%), and a dimer ketone (6.2%). Reprints. (jes)