Free radical reactions using n - tetrabutylammonium peroxydisulfate

Abstract

Various allylic or benzylic alcohols were oxidized into the corresponding carbonyl compounds in the presence of n-tetrabutylammonium peroxydisulfare $((TBA)_2S_2O_8$, $(n-Bu_4N)_2S_2O_8)$ in organic solvents. Under the similar conditions allylic, benzylic, and various alcohols containing multifunctional groups were reacted with tetrabutylammonium peroxydisulfate in anhydrous THF under argon atmosphere to give 2-tetrahydrofuranyl ethers in excellent yields. The procedure for the tetrahydrofuranylation is remarkably simple and can be carried out under the mild conditions through radical coupling. $\beta$-Masked formylating products were obtained from the reactoin of electron-deficient olefins and n-tetrabutylammonium peroxydisulfate in anhydrous 1,3-dioxolane. In these reactions, 1,4-addition products were obtained in excellent yields. When various nitroolefins were reacted with tetrabutylammonium peroxydisulfate in anhydrous 1,3-dioxlane under argon atmosphere, $\alpha$-masked formylated ketones were obtained in moderate yields. In connection with the addition of 1,3-dioxolan-2-yl radical to electron-deficient olefins, these procedures were applied to a simple method for the masked acetylation of electron-deficient olefins under a nearly neutral and mild conditions. 1,4-Addition products, which were formed from the reaction of 2-methyl-1,3-dioxolan-2-yl radical and electron-deficient olefins, were also obtained in moderate yields. The addition of tetrahydrofuran to electron-deficient olefins by tetrabutylammonium peroxydisulfate has been found to result in 1,4-addition products in good yields.