A radical mechanism of hydrocarbon oxidations with the environmentally friendly and cheap homogeneous nontransition metal system [Al(H2O)(6)](3+)/H2O2/MeCN-H2O was proposed for the first time on the basis of DFT calculations. A dramatic activation of H2O2 toward homolysis in the key intermediate [Al(H2O)(4)(OOH)(H2O2)(2+) due to the presence of the easily oxidizable OOH coligand provides, without a change of metal oxidation state, the generation of HO center dot radicals, which then oxidize hydrocarbons. Nonradical mechanisms of the olefin epoxidation with the same catalytic system were also investigated.