The autoxidation of olefine ie known to be catalyeed by various transition metal complexes. Several investigations 1 and a recent study by UB 2 have well established the free radical character of this reaction, as well as the prior formation of en allylic hydroperoxide, decomposed cub eequently by the catalyet. For instance cyclohexene ir oxidized to give,in a typical free radical chain process, mainly 2-cyclohexen-I -01 and 2-cyclohexen-I -one. OOH 0 I to2 -0 I -In the course of a detailed rtudy of the decomposition of cyclohexene hydroperoxide catalyzed by Rh Cl (P Ph3)3, we obrerved that an autoxidation reaction carried out in the prerence of a recond transition metal compound led to quite a different decomporition path. We now wieh to report Borne rerulte with cyclohexene pertaining to this new relective method of oxidation. The results given in Table I, for some of the catalyst combinations ueed clearly rhow the different product distribution obtained with and without the recond catalyrt. This ir rpecially emphasized in the epoxide percentage. This difference in reaction path can be explained by two rucceaeive catalytic procereea. The fir& one conrirtr of a hydroperoxide formation ar in a typical autoxidation procello, the second, a selective olefin oxidation wherein the hydroperoxide ir the oxidising Tbie echeme ir well in accord with the previour rtudiee carried out on the individual steps of the reaction ; metale lieted have been ured ar catalyrte in autoxidation and in