The system Ti(IV) tetra-tert-butoxide3tert-butyl hydroperoxide in mild conditions (20oC) oxidizes C3H bonds of methyl (toluene), methylene (hexane, ethylbenzene, benzyl ethyl ether), and methine (1,1-diphenylethane, triphenylmethane) groups. The role of oxidant is played by the oxygen generated by the system. The process involves free radicals and produces hydroperoxides and Ti(IV) peroxides. The latter decompose both with preservation and decomposition of the hydrocarbon skeleton.Previously we showed [135] that the Al(OBu-t)33 t-BuOOH system effectively and in mild conditions (20oC) oxidizes C3H bonds in alkanes, alkylarenes, as well as oxygen-containing functional derivatives (aldehydes, ketones, saturated ethers and esters, etc.). The fact that best oxidized are C3H bonds in the allyl, benzyl, and benzhydryl radicals points to a homolytic nature of the processes. The formation of carboncentered and peroxyl radicals from the substrates was confirmed by ESR [6]. At present we are searching for new mild oxidants comprising other metals, both maingroup and transition. Therewith, we set ourselves the task to establish the role of the metal, common features of the processes, and reaction centers on the system and substrates.It is known that aluminum and Ti(IV) alkoxides sometimes exhibit similar chemical properties. Thus, their reactions with alcohols, carbonyl compounds, and carboxylic acid anhydrides and halides occur in a similar fashion. Both metals have vacant p and d orbitals. Therefore, one may expect that reactions of aluminum and Ti(IV) alkoxides will similarly react with hydroperoxides. The aim of the present work was to explore the oxidative power of the Ti(IV) tetra-tertbutoxide (I)3tert-butyl hydroperoxide (II) system. The ÄÄÄÄÄÄÄÄÄÄÄÄ reaction of alkoxide I with hydroperoxide II in a 1 : 2 ratio in benzene at room temperature is accompanied by evolution of oxygen whose yield attains 0.853 0.90 mol/mol I [7]. Distillation after reaction completion recovered~0.80 mol of Ti(IV) alkoxide [Eq. (1)].Ti(OBu-t) 4 + 2t-BuOOH,(1)When the I : II ratio was increased to 1 : 10, the yield of oxygen was 4.2 mol. No solvent oxidation products were found.The reaction between the components of the systems involves formation of Ti(IV) peroxide and trioxide, like in the system comprising aluminum alkoxide [6,8]. Decomposition of the trioxide results in oxygen evolution (therewith, Ti(IV) alkoxide is regenerated [7]) and formation of oxygen-centered alkoxyl and peroxyl radicals [Scheme (2)].(t-BuO) 4 + t-BuOOH 76 47 t-BuOH + (t-BuO) 3 TiOOBu-t, (t-BuO) 3 TiOOBu-t + t-BuOOH t-BuOH + (t-BuO) 3 TiOOOBu-t.
