Chemistry of 2-methoxy-2,5-cyclohexadienones. II. Oxidation of 2-methoxy-4,4-dimethyl-2,5-cyclohexadienone.

Abstract

2-Methoxy-4, 4-dimethyl-2-cyclohexenone (II) afforded 5, 6-epoxy-6-methoxy-4, 4-dimethyl-6-hexanolide (III) upon reaction with m-chloroperbenzoic acid in 1, 1, 1-trichloroethane. On the other hand, the treatment of II with the same reagent in an aqueous disodium orthophosphate-methylene chloride system at 4°C gave 2, 3-epoxy-2-methoxy-4, 4-dimethylcyclohexanone (V), which could be converted to methyl 2-hydroxy-1-methoxy-3, 3-dimethylcyclopentanecarboxylate (VI). 2-Methoxy-4, 4-dimethyl-2, 5-cyclohexadienone (I) afforded 5, 6-epoxy-2-methoxy-4, 4-dimethyl-2-cyclohexenone (VIII) upon reaction with hydrogen peroxide in a basic medium. The reaction of I with m-chloroperbenzoic acid at room temperature gave 5, 6-epoxy-6-methoxy-4, 4-dimethyl-2-cyclohexenone (X). Neither VIII nor X gave the expected 2, 3, 5, 6-diepoxy-2-methoxy-4, 4-dimethylcyclohexanone (VII), but afforded 2, 3, 5, 6-diepoxy-6-methoxy-4, 4-dimethyl-6-hexanolide (IX).