Mechanism of C-C Cleavage of Cyclic 1,2-Diketones with Alkaline Hydrogen Peroxide. The Acyclic Mechanism and Its Application to the Basic Autooxidation of Pyrogallol

Article abstract of DOI:10.1021/ja00353a030

The reaction of 3,5-di-tert-butyl-o-benzoquinone (3) with alkaline hydrogen peroxide was found to give a considerable amount of methyl ester 5 when H2O2 was added dropwise.In contrast, the corresponding diacids were not obtained from o-benzoquinone or 1,2-naphthoquinone on reaction with alkaline H2O2.An 18O-tracer study of the reaction of 3 and 9,10-phenanthrenequinone indicated that the C-C cleavage reaction proceeds via the acyclic Baeyer-Villiger type mechanism and clearly eliminated possible dioxetane or epoxide mechanisms.A similar study of the base-catalyzed autooxidation of 4,6-di-ter-butylpyrogallol revealed that the C-C bond is cleaved in a similar way by hydrogen peroxide formed from O2 and the polyphenol.