Oxidations by the system 'hydrogen peroxide-[Mn2L2O3]2Â + (LÂ =Â 1,4,7-trimethyl-1,4,7-triazacyclononane)-carboxylic acid'

► Combination Mn complex/oxalic acid catalyzes epoxidation of methyl oleate with H2O2. ► The reaction proceeds under very mild conditions (25 ºC). ► Yield and selectivity attained 100%, turnover numbers were up to 2000. ► The oxidation proceeds with the participation of high-valent oxo-manganese species.