A computational study of N-hydroxyphthalimidecatalyzed aerobic oxidative cleavage of alkenes is carried out employing density functional theory and high-level coupled-cluster methods, such as coupled-cluster singles and doubles with perturbative triples [CCSD(T)]. Our results demonstrate that the reaction proceeds through the alkoxyl radicals, as opposed to the mechanism suggested by Jiao and co-workers (Org. Lett. 2012, 14, 4158-4161), in which the reaction proceeds via formation of the dioxetane ring. The barriers for the formation of dioxetane derivatives are computed to be higher than SO kcal mol(-1), while the barriers for the formation of alkoxyl radicals are as low as 13 kcal mol(-1). Our results also demonstrate that epoxide derivatives can be formed as intermediates or byproducts under the reaction conditions.