Oxidation is a most important transformation in organic synthesis; however, these reactions essentially involve the use of large quantities of heavy metals and complex organic compounds, which generate large amount of waste, and are not at all environmentally benign. Molecular oxygen has received much attention as an ultimate oxidant, since it is photosynthesized by plants, produces little waste, is inexpensive and of large atom efficiency than that of other oxidants. With this perspectives, we have found that methyl aromatics effectively oxidized to benzoic aicd by photooxidation with molecular oxygen as terminal oxidant in the presence of 2-chloroanthraquinone under irradiation of a fluorescent lamp. Furthermore, methyl aromatics were found to be oxidized to the corresponding methyl benzoate by one step with molecular oxygen as terminal oxidant in the presence of anthraquinone-2,3-dicarboxylic acid under irradiation of a 500 W xenon lamp.
