Process for the preparation of a hydroperoxide functionalized olefinic compound in an oxidation reactor containing a particulate catalyst bed comprising a light induced photosensitized catalyst component supported on a particulate substrate material forming a permeable catalyst bed. The photoenergized catalyst component is a photoreductant material which is effective for the conversion of triplet oxygen to singlet oxygen under illumination with ultraviolet or visible light. An oxygen containing feed stream containing triplet oxygen is supplied to the catalyst bed. The catalyst bed is irradiated at an intensity to convert triplet oxygen to singlet oxygen to produce a singlet oxygen enriched gas stream. The enriched gas stream is supplied to a second reactor which contains a dispersion of an olefinic component having an allylic hydrogen which is contacted with the enriched gas stream under conditions effective to cause an allylic rearrangement and introduce hydroperoxide functionalization into the olefinic component.