CYCLIC PEROXIDE .86. ALPHA-PYRONE ENDOPEROXIDES - SYNTHESIS, THERMAL-DECOMPOSITION, AND CHEMI-LUMINESCENCE

Singlet oxygenation of α-pyrones 2 affords the corresponding endoperoxides 1 in high yield. On heating, these peroxides quantitatively decarboxylate into the respective 1,2-diacylethylenes 4. The suspected intermediary o-dioxins 3 could not be trapped with maleic anhydride, tetracyanoethylene, and N-phenyl-1,2,4-triazoline-3,5-dione, suggesting that the decarboxylation of the endoperoxides 1 takes place with concomitant peroxide bond fission. Easily oxidized polycyclic aromatic hydrocarbons, e.g., rubrene, perylene, and 9,10-diphenylanthracene, induce the decarboxylation of the endoperoxides 1 with light emission by an electron exchange mechanism. © 1979, American Chemical Society. All rights reserved.