Bioinspired Non-heme Diiron Catalysts for Olefin Epoxidation with Hydrogen Peroxide in the Presence of Acetic Acid

Mild epoxidation of olefins catalyzed by non-heme oxo-bridged diiron(III) complexes with tetradentate N,N?-bis(2-pyridylmethyl)-diamine ligand moiety and exchangeable water molecule in each iron center, [Fe2O(Ln)2(H2O)2](ClO4)4 (n = 1 and 2), have been explored at room temperature with environmental-friendly hydrogen peroxide (H2O2) as oxygen source. A series of substrates such as cyclooctene, cyclohexene, 1-octene, norbornene and 1,2-dihydronaphthalene have been chosen as a representative set of olefins. The epoxide yield and product selectivity has been greatly enhanced upon the addition of acetic acid to the reaction mixture. The catalytic results suggest the involvement of metal-based intermediate in the epoxidation reaction.