Arene endoperoxides

H2-isoprostane bicycUc endoperoxides, 612 hpid hydroperoxide determination, 681 Arene endoperoxides... 

Enthalpies of ozonation, 165 Enthalpies of reactions acyl peroxides, 162-3 arene endoperoxides, 166-7 tert-butyl perbenzoate ETR reactions, 909-11... 

Singlet oxygen can also be obtained by thermal decomposition of unstable molecules, such as arene endoperoxides (e.g. 507) (Section 6.7.2) or ozonides (e.g. 508),135,1384,1385 by photolysis of ozone1386 or arene endoperoxides (such as 507),1384,1387 or by microwave discharge in the presence of ground-state oxygen (Scheme 6.248).1388... 

While both hydrogenation and epoxidation reactions of (7) (and substituted forms) occur on the oxepin valence tautomer, cycloaddition reactions proceed more readily on the arene oxide form (where the diene is closer to planarity). Thus the dienophiles DM AD and maleic anhydride (MA) readily yielded [4 + 2] cycloadducts with (7) as shown in Scheme 22 (67AG(E)385). A similar type of singlet oxygen cycloaddition reaction gave an unstable endoperoxide (106) which upon heating yielded trans-benzene trioxide quantitatively (equation 14). (75JOC3743). 

Endoperoxides (sometimes called 1,4-epiperoxides or dioxapropellanes) are six-membered ring peroxides, which arise from singlet oxygenations of arene and diene compounds and have been synthesized as pure compounds (e.g., 43-52 and 62-72 Schemes 11.4 to 11.7). Many endoperoxide structures have been reported [38-41] the rosettes of Schemes 11.5 and 11.7 show examples where endoperoxides were formed in good yield. 

The rosette of Scheme 11.5 shows the endoperoxidation of the corresponding arene compounds in Scheme 11.4. 

Various applications of the endoperoxide-epoxide rearrangements in the multistep total synthesis of natural products are reported in the literature, for example, the synthesis of stemolide, a natural syn-diepoxide with antileukemic activity. A photochemical route from arenes to inositol intermediates was... 

With the endoperoxide of heterocoerdianthrone 37, the quantum yield of the (irreversible) photolytic decomposition becomes extremely small and the (reversible) photoinitiated cleavage to singlet oxygen and the arene estabhshes an efficient photochromic system. A further improvement of this concept was achieved with the blue dimethylhomeocoerdianthrone 38. This compound gave the colorless endoperoxide 39 by sensitized photooxygenation that reverts back quantitatively to the starting material 38 on irradiation at 313 nm (Scheme 15). ... 

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