epoxidation of olefins with tetra n-butyl-ammonium periodate in the presence of tetrakis (4-substituted phenyl) porphyrinatiomanganese(iii) acetates and imidazole

the epoxidation of olefins with tetra n-butylammonium periodate, n-bu4/nio4, is catalyzed by six different tetrakis (4-substituted phenyl) porphyrinatomanganese(iii) acetate, mn(t4-xpp)oac, complexes in the presence of imidazole as an axial ligand with low to high yields and complete selectivity at room temperature. while the electronic effects of the highly electron-withdrawing no2 substituents are clearly reflected in the reduction of epoxidation yields, other substituents, i.e meo, me, cl, and br, do not significantly modify epoxide yields relative to mn(tpp)oac and give very similar results.