MANGANESE(II AND III)-MEDIATED SYNTHESIS OF CYCLIC PEROXIDES FROM ALKENES, ACTIVE METHYLENE-COMPOUNDS, AND MOLECULAR-OXYGEN

The reaction of 1,1-diphenylethene, 1,1-bis(4-chlorophenyl)ethene, 1,1-bis(4-methylphenyl)ethene, 1,1-bis(4-methoxyphenyl)ethene, and 1,1-bis(4-fluorophenyl)ethene with 2-methyl-1,3-cyclohexanedione, 2-methyl-1,3-cyclopentanedione, 2-acetylcyclohexanone, ethyl 2-acetyl-3-oxobutanoate, 3-methyl-2,4-pentanedione, 1,3-cyclohexanedione, and 2,4-pentanedione in the presence of Mn(OAc)2 and molecular oxygen yielded the corresponding cyclic peroxides in moderate-to-good yields. Similar reaction of 1,1-disubstituted alkenes with 1,3-cyclopentanedione in the presence of Mn(OAc)3 and molecular oxygen gave 2,2,9,9-tetraphenyloctahydro-3,4,7,8-tetraoxabenz[c]indene-4a,6a-diols. Acid-catalyzed decomposition of 4-acetyl-6,6-diaryl-3-methyl-1,2-dioxan-3-ols yielded 3-acetyl-5-aryl-2-methylfurans in moderate yields. Treatment of the 4-acetyl-6,6-diaryl-3-methyl-1,2-dioxan-3-ols with alkali gave 6,6-diaryl-3-methyl-1,2-dioxan-3-ols which gave 1-aryl-1,4-pentanediones upon treatment with hydrochloric acid in acetic acid. The synthetic utility and mechanisms of the reactions are discussed.