Diacyl peroxides, cyclic

CYCLIC PEROXIDES, DIACYL PEROXIDES DIALKYL PEROXIDES, Z, /-DI(BENZOYLPEROXY)ARYLIODINES DIFLUOROAMINO COMPOUNDS, DIFLUOROAMINOPOLYNITROAROMATIC COMPOUNDS... 

The photolysis of carboxylic acids and derivatives as lactones, esters and anhydrides can yield decarboxylated products 253>. This reaction has been utilized in the synthesis of a-lactones from cyclic diacyl peroxides 254) (2.34) and in the synthesis of [2,2]paracyclophane by bis-decarboxylation of a lactone precursor (2.35) 255). This latter product was also obtained by photoinduced desulfurization of the analogous cyclic sulfide in the presence of triethyl phosphite 256). 

Cyclic compounds, unnatural, 24 59 Cyclic cooligomerization, 16 238 Cyclic corrosion tests, 16 218 Cyclic diacyl peroxides, 18 473, 477 Cyclic dimethylsiloxanes, 22 575 Cyclic diperoxides, 18 461 Cyclic diperoxyketals, 18 457 Cyclic disulfides, antimicrobial properties of, 23 713... 

Heating cleaves a weak 0-0 bond homolytically to give two oxy radicals. Fragmentation of the C1-C6 and C9-C14 bonds gives two radicals which recombine to give a cyclic diacyl peroxide. 

Most of the isolated diacyl (including sulfonyl) peroxides are solids with relatively low decomposition temperatures, and are explosive, sensitive to shock, heat or friction. Several, particularly the lower members, will detonate on the slightest disturbance. Autocatalytic (self-accelerating) decomposition, which is promoted by tertiary amines, is involved [1]. Solvents suitable for preparation of safe solutions of diacetyl, dipropionyl, diisobutyryl and di-2-phenylpropionyl peroxides are disclosed [2], The class is reviewed, including hazards and safety measures [3], Cyclic diacyl peroxides are more stable, but scarcely to be trusted. Individually indexed compounds are ... 

Cyclic enaminones react with diacyl peroxides to yield products of monoacyloxylation, which subsequently give cyclohexadienones199 (equation 140). 

Though many open-chain diacyl peroxides have been described, very few cyclic compounds of this type are known. Monomeric cyclic phthaloyl peroxide (84) is prepared by treatment of phthaloyl chloride in chloroform with aqueous sodium peroxide solution in the presence of phosphate buffer, or by reaction of phthaloyl chloride with ethereal hydrogen peroxide in the presence of sodium carbonate.70-72 Russell71 has also obtained cyclic diacyl peroxides from the dichlorides of the C10, C12, and C14 dicarboxylic acids. Only polymeric diacyl peroxides were obtained from lower dicarboxylic acids. 

Another route to cyclic diacyl peroxides was discovered by Ramirez et al.73 A mixture of phenanthraquinone and trimethyl phosphite in methylene chloride gives an adduct (85) at room temperature, and this adduct is ozonized at —70°. Diphenoyl peroxide (86) is formed in 50% yield. 

The diacyl peroxide has been used as a source of FC02-radicals. Fluorination of the peroxide by photolysis with F2 gives access to the acyl hypofluorite, FC(0)0F, bp ca. —55 °C, in reasonable yields. The acyl hypofluorite is a precursor to a cyclic isomer, the simplest perfluorodioxirane, CF2O2, made by the method shown in equation (59). ... 

The results obtained with camphorquinone in -xylene are of particular interest since this reaction has been investigated 129> under otherwise identical conditions in the presence and absence of oxygen. In carefully degassed -xylene solution at 4358 A the major products were the 1,2-adducts 56 and 57 the quantum yield for disappearance of dione was 0.07. In air-saturated -xylene the quantum yield increased to 0.16, 56 and 57 were not formed, instead the products were camphoric acid (104) and camphoric anhydride (105). No explanation has been offered for the different course of reaction in benzene where cyclic lactones 106 and 107 were obtained 97). Intermediacy of the cyclic diacyl peroxide 108 has been suggested 97h It is tempting to speculate that the diacyl radical 109 may have been trapped by oxygen. 

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