Intramolecular coupling between cyclohexadiene–Fe(CO)3 complexes and pendant alkenes: formation of azaspiro[5,5]undecane derivatives

A new methodology for making stereodefined 2-azaspiro[5,5]undecan-1-one (δ-lactam) derivatives was developed by intramolecular coupling between cyclohexadiene–Fe(CO)3 moiety and pendant olefins. δ-Lactams were found more difficult to form than γ-lactams, thus resulting in poorer yields and requiring longer reaction times. By introducing an ester group on the pendant olefin, increased yield was achieved.