The catalytic oxidation of cyclohexene with hydrogen peroxide promoted by manganese and iron porphyrins has been studied in the presence of halogenated carbonyl compounds as co-catalysts in a dichloromethane/water biphasic medium. The efficiency of the overall catalytic process is strictly related to the nature of the co-catalyst and to the high reactivity of its perhydrate form toward metalloporphyrins in forming an high valent oxo-pororphyrin derivative. Hydrogen peroxide fixation by hexafluoroacetone hydrate provides an useful system to hamper catalyst bleaching and/or oxidant decomposition. Thus, a complete olefin conversion into oxygenated products is accomplished with a very limited excess of oxidant respect to the organic substrate.