Experiments on the synthesis of tetracycline. Part IX. The synthesis and rearrangement of 6-acyloxycyclohexa-2,4-dienones

Abstract

Contrary to earlier reports, the reaction of phenols or phenolate anions with diaroyl peroxides affords mainly ortho-substituted derivatives in good yield by anon-free-radical process. In the case of 2- and 2,6-substituted phenols 6-acyloxycyclo-2,4-dienones are produced. It has been shown that a smooth thermal intramolecular equilibration takes place between these ortho-dienones and the corresponding para-dienones. The generality of the phenomena has been demonstrated and the mechanism of the rearrangement studied.