Thenoyl peroxides, decomposition

Thermolysis of 2-thenoyl peroxide in various solvents indicated that the 2-thenoyloxy radical was sufficiently stable towards decarboxylation, and was trapped as such by the substrates (73IJS295). There was very little indication of the production of 2-thienyl radicals. The kinetics of decomposition of a number of substituted 2-thenoyl peroxides and t-butyl 2-perthenoates have been investigated electron-releasing substituents increase the rate of decomposition, while electron-withdrawing groups decrease the rate. 3-Thenoyl peroxide, on the other hand, seems to provide 3-thienyl radicals on decomposition. Low yields of arylation products like (342) were obtained. 

The effect of substituents upon the rate of thermal decomposition of thenoyl peroxides was similar to that reported for benzoyl peroxide. Hammett constants were used for the 5-substituted-3-thenoyl peroxides (I) and 4-substituted-2-thenoyl peroxides (II), while constants were used for the 5-substituted-2-thenoyl peroxides (III). A p-value of about —0.4 was obtained for the thenoyl peroxides using... 

THERMAL DECOMPOSITION OF SUBSTITUTED THENOYL PEROXIDES IN CARBON... 

Radical Reactkms.— The reaction of a-chloro ethers with zinc in the presence of thiophen yields di-2-thienyl alkanes (106). Photolysis of 3-iodopyridine in the presence of thiophen yields a mixture of 3-(2-thienyl)-pyridine and 3-(3-thienyl)pyridine in a 7 1 ratio. The synthesis and rate of decomposition of 2- and 3-thenoyl peroxides and of mixed thenoylfuroyl peroxides have been described. " Aryl 2-thenoates were obtained in high yields by the reaction of substituted benzenes with 2-thenoyl peroxide in the... 

---