Lewis Acid Promoted Intramolecular Cyclization of (η⁴-Diene)Fe(CO)₃ Complexes Bearing Functionalized Side Chains

Abstract

Addition of aluminum chloride to the (η 4 -cyclohexadiene)Fe(CO) 3 complex bearing an acid chloride side chain at C-5 gives a cyclic keto complex, whereas Lewis acid assisted intramolecular cyclization of acyclic (η 4 -butadiene)Fe(CO) 3 complexes containing an aldehyde, an ester, or a nitrile functionality produces (σ,η 3 -allyl)tricarbonyliron complexes. Treatments of the (η 4 -butadiene)Fe(CO) 3 complexes bearing a chromium carbene moiety in refluxing toluene lead to formation of furan derivatives by intramolecular addition of the diene ligand to the chromium carbene carbon center.