| Extension of the intramolecular coupling between a cyclohexadiene-Fe(CO) 3 moiety and pendant olefins to make delta-lactam derivatives was investigated. delta-Lactams were found more difficult to form than gamma-lactams, thus resulting in poorer yield and requiring longer reaction time. By introducing an ester group on the pendant olefin, increased yield was achieved.;Intramolecular double cyclization between a cyclohexadiene-Fe(CO) 3 complex and a pendant diene yielded a tricyclic molecule containing a spirocenter, with defined relative stereochemistry of four contiguous carbon centers.;A convenient one-pot procedure to prepare angularly substituted bicyclic and tricyclic molecules with excellent diastereoselectivity in good yield was developed, by Fe(CO)5 promoted cyclization. Three transformations (complexation, isomerization and cyclization) were realized in a single operation. The product of this reaction might be a potential intermediate for synthesis of the alkaloid gelsemine.;A new short protocol, rearrangement of the cyclohexadiene followed by cyclization, was discovered to give carbon spirocyclic molecules in fair to good yield.;Diastereoselective cyclizations of diastereomeric amide complexes, which were prepared from chiral amines and racemic acid complexes, were investigated to show that the chirality, originating from the amine, can dictate the stereochemistry of the cyclization product by steric approach control. In one case, kinetic dynamic resolution during intramolecular coupling between the cyclohexadiene-Fe(CO) 3 moiety and pendant olefin was demonstrated, which also showed an promise of a potential enantioselective methodology toward spriocyclic targets using racemic iron complexes. |
