The syntheses and thermal decompositions of six-membered cyclic diacyl peroxides
meso- and d1-2,3-Dimethylsuccinyl peroxides (5) and (6), cis- and trans-1,2-hexahydrophthaloyl peroxides (7) and (8), and bicyclo[3.1.0]hexanediacyl peroxide (9) have been synthesized. Products of their thermal decomposition in dichloromethane and THF suggest they decompose by a stepwise mechanism v...
| Summary: | meso- and d1-2,3-Dimethylsuccinyl peroxides (5) and (6), cis- and trans-1,2-hexahydrophthaloyl peroxides (7) and (8), and bicyclo[3.1.0]hexanediacyl peroxide (9) have been synthesized. Products of their thermal decomposition in dichloromethane and THF suggest they decompose by a stepwise mechanism via the intermediacy of a carboxy diradical. The decomposition of erythro- and threo-2,3-dimethylpropiolactone was stereospecific and requires that the pathway and/or intermediate in this decomposition be different from that of the decomposition of peroxides (5) and (6). Thermal decomposition of (5)-(8) in methanol afforded saturated and unsaturated methyl ethers. Mechanisms involving the intermediacy of a radical cation are discussed.
Direct and sensitized irradiation of (5)-(8) were performed. The peroxides were quite photolabile. Benzophenone, anthracene, and tetracene were effective sensitizers. An electron transfer rather than an energy transfer mechanism for the effectiveness of anthracene and tetracene is proposed.
Induced decomposition of the cyclic diacyl peroxides by triphenylphosphine and dimethylsulfide to stereo-specifically lead to the corresponding cyclic anhydrides was observed.
Copper (I) rapidly induced the decomposition of peroxides (5)-(8) to afford the corresponding olefins in low to moderate yields.
Induced decomposition of peroxides (5)-(8) by aromatic hydrocarbons was observed. Emission of light was observed from the reaction of d1-(6) and rubrene. The observations are consistent with chemically initiated electron transfer luminescence (CIEEL).
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