Water-Soluble Iron Porphyrin Complex-Catalyzed Epoxidation of Olefins with Hydrogen Peroxide and tert-Butyl Hydroperoxide in Aqueous Solution

Catalytic epoxidation of olefins with H2O2 and t-BuOOH has been studied in the presence of a water-soluble iron(III) porphyrin complex, (5,10,15,20-tetrakis(2,6-dichloro-3-sulfonatophenyl)porphinato)iron(III) [Fe(TDCPPS)], in buffered aqueous solutions. Epoxides are the predominant products at low pH values, and the formation of the oxide products is found to depend on the pH of the reaction solutions. A high-valent iron(IV) oxo porphyrin cation radical complex is proposed as a reactive intermediate responsible for the olefin epoxidation.