FORMATION OF 1,2-DIOXANES BY THE USE OF TRIS(2,4-PENTANEDIONATO)-MANGANESE(III) OR MANGANESE(III) ACETATE

The reactions of 1,1-diphenylethene, 1,1-bis(4-chlorophenyl)ethene, 1,1-bis(4-methoxyphenyl)ethene, 1,1-bis(4-methylphenyl)ethene, 1,1-bis(4-fluorophenyl)ethene, styrene, 1-octene, cyclohexene, and cyclooctene with tris(2,4-pentanedionato)manganese(III) ([Mn(acac)3]) in acetic acid at room temperature give 4-acetyl-3-methyl-1,2-dioxan-3-ol in 8-92% yields, together with 3-acetyl-4-hydroxy-3-hexene-2,5-dione. The similar reactions of 1,1-diphenylethene with 2,4-pentanedione, 3-methyl-2,4 pentanedione, 3-ethyl-2,4-pentanedione, 1-phenyl-1,3-butanedione, acetoacetanilide, and 1,3-cyclohexanedione in the presence of manganese(III) acetate also give the corresponding cyclic peroxide in good to moderate yields. The mechanisms of manganese(III)-induced 1,2-dioxane ring formation and concomitant radical side reaction are discussed.