Metalloporphyrin-Catalyzed Decomposition of Cyclic Diperoxides (1,2,4,5-Tetraoxanes)

Article abstract of DOI:10.1021/jo00362a015

Cyclic diperoxides of type 1 (a, R=H; b, R=Ph; c, R=n-Bu; d, R=Me) were found to be very stable (E_a = 42-48 kcal/mol, log A = 17-19).Decomposition of 1 was greatly promoted by addition of ZnTPP or CoTPP, leading to formation of ketone PhCOR and ester (or acid) PhCO2R as the major products.In the presence of PH2S or Ph2SO as oxygen acceptor, the oxygen transfer reaction occurred and the production of PhCO2R (=PhCO2Bu) was completely suppressed in the case of 1c, while it (the production of PhCO2H) was not measurably suppressed in the case of 1a.Chemiluminescence (CL) that is due to singlet ZnTPP formation was detected from the reaction of ZnTPP with 1a but not with 1c.The observed first-order decay rate of CL for the reaction of 1a with ZnTPP and its para-substituted derivatives Zn(p-X)TPP increased with the increase in electron-donating nature of the substituents (CN < Cl < H < CH3 < OCH3).A tentative mechanism for this ZnTPP-catalyzed decomposition reaction, which takes the different behaviors of 1a and 1c into account, is proposed.