Thermolysis of dioxiranes in solutions of their parent ketones or in mixtures of the parent ketone and a foreign ketone leads to the formation of esters. The results are explained by postulating a freeradical mechanism involving H atom abstraction from the ketones. The resulting radicals are converted to the observed esters by reaction with acyloxy radicals derived from homolysis of the dioxiranes. Autodecomposition of dimethyldioxirane in ...