Stereochemistry of the Reaction of 7-Substituted Norbornadienes with Iron Carbonyls. 3. Reaction of Fe(CO)5 with 7-(Benzoyloxy)Norbornadiene

摘要

Thermal reaction of 7-(benzoyloxy)norbornadiene with Fe(CO)5 affords a cage dimer (1, 29%), an anti,exo,trans,endo,anti (AXTNA) dimer ketone (2, 1%), a syn,endo,trans,endo,syn (SNTNS) dimer ketone (3, 2%), and anti,exo,trans, exo, anti (AXTXA) dimer ketone (4, 3%, and a novel cage dimer ketone (5, 0.4%). Thermal reaction of 7-(p-methoxybenzoyloxy)norbornadiene (6) with Fe(CO)5 afforded the corresponding cage dimer (7,23%) and an anti,exo,trans,exo,anti (AXTXA) dimer ketone (8, 4%). The regiospecificity that has been noted previously in the case of Fe(CO)5-promoted coupling of 7-t-butoxynorbornadiene to carbon monoxide clearly is not a feature of the corresponding reactions reported herein.