Manganese-(II) and (III)-mediated free-radical cyclisation of alkenes, β-keto esters and molecular oxygen

Abstract

The reactions of substituted ethenes with β-keto esters in the presence of a mixture of manganese(II) and manganese(III) acetates, and molecular oxygen yielded substituted 1, 2-dioxan-3-ols 3 in 14–95% yields. Cobalt(III) acetate, potassium permanganate, lead(IV) acetate, copper(II) acetate, chromium(VI) trioxide, thallium(III) acetate, ammonium cerium(IV) nitrate and iron(III) perchlorate were also used in place of manganese(III) acetate. Effects on the product yields of substituents in the alkenes and β-keto esters have been examined and reaction mechanisms are discussed.