Alkene epoxidation catalyzed by manganese complexes with electronically modified 1,10-phenanthroline ligands

The syntheses and alkene epoxidation activities of four manganese(II) complexes with electronically modified 1,10-phenanthroline ligands are reported. Each phenanthroline has a different substituent in the 5-position; the placement ensures that the modifications influence the reactivity through largely electronic effects. All four manganese complexes catalyze the conversion of alkenes to epoxides by commercially available peracetic acid. With each of the four alkenes investigated, the yield of the epoxide product is greater when the 5-substituent on the catalyst is strongly electron-donating, contrary to what has been observed with reactions catalyzed by manganese–salen complexes.