Chemistry of 2-Methoxy-2, 5-cyclohexadienone. V. Photochemical Rearrangement and Oxidation of 2-Methoxy-4-methyl-4-phenyl-2-cyclohexenone and 2-Methoxy-4-methyl-4-phenyl-2, 5-cyclohexadienone

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A methanolic solution of 2-methoxy-4-methyl-4-phenyl-2-cyclohexenone (I) was irradiated with a 100 W mercury lamp to give 4-methyl-4-phenyl-2-cyclohexenone (III) and 1-methoxy-5-methyl-6-phenylbicyclo [3.1.0] hexan-2-one (IV). When a benzene solution of I was irradiated, only IV was obtained. On the other hand, 2-methoxy-4-methyl-4-phenyl-2, 5-cyclohexadienone (II) gave 2, 2-dimethoxy-6-methyl-6-phenylbicyclo [3.1.0] hexan-3-one (V) and 6, 6-dimethoxy-5-methyl-5-phenyl-3-cyclohexenone (VI) on photoirradiation in methanol. In benzene, 6-methoxy-6-methyl-5-phenyl-2, 4-cyclohexadienone (XI) was obtained.
Compound II was treated with m-chloroperbenzoic acid in a bilayer system of methylene chloride-aqueous disodium orthophosphate at room temperature to give 5, 6-epoxy-6-methoxy-4-methyl-4-phenyl-2-cyclohexenone (XVI) and its stereoisomer (XVI'). 5, 6-Epoxy-2-methoxy-4-methyl-4-phenyl-2-cyclohexenone (XVIII) was obtained by treatment of II with hydrogen perokide in a basic medium. 2, 3 : 5, 6-Diepoxy-6-methoxy-4-methyl-4-phenyl-6-hexanolide (XVII) rather than the expected diepoxide (XII) was obtained by the alternative oxidation of XVI or XVIII.