Formal aza-Michael additions to tropone: Addition of diverse aryl- and alkylamines to tricarbonyl(tropone)iron and [(C7H7O)Fe(CO)3]BF4

A formal aza-Michael addition to tropone by way of tricarbonyl(tropone)iron and/or the tetrafluoroborate salt formed via protonation of the complex is reported. Tricarbonyl(tropone)iron smoothly undergoes the direct aza-Michael reaction with unhindered aliphatic amines under solvent free conditions in good yields. Meanwhile, the known cationic complex (C₇H₇O)Fe(CO)₃]BF₄ (whose reaction with a small number of nucleophiles was previously reported) undergoes addition with an even broader array of amine nucleophiles. Finally, it was discovered that protecting the aza-Michael adduct as a carbamate was necessary for oxidative demetallation of the complex.