In the catalytic reaction of an iron(III) porphyrin with t-BuOOH, CumOOH, H 2 O 2 and C 6 F 5 IO, cyclohexene was used as a probe substrate. The selective hydroxylation of cyclohexene by hydroperoxides proceeds through radical path and this has been utilized for successful dioxygen activation/autooxidation. For other oxidants epoxide was the major product and the reactions proceed through non-radical path.