Directly catalytic oxidation of cyclohexene to adipic acid with hydrogen peroxide over environmentally benign peroxytungstate-organic complex catalysts is performed with excellent yields and selectivities, without any organic solvent and harmful phase-transer catalyst.

★★★★☆ Deng, YQ; Ma, ZF; Wang, K, et al. GREEN CHEMISTRY, 1999, 1, 275-276.