Mechanism and selectivity of radical alkylation of 3,4-Dichloro-2,5-dihydrofuran-2,5-dione

The mechanism of radical alkylation of 3,4-dichloro-2,5-dihydrofuran-2,5-dione with cyclohexane and 2,3-dimethylbutane follows an addition-elimination pattern with reversible formation of alkyl radicals. The proposed kinetic scheme takes into account the possibility for isomerization of primary 2,3-dimethylbutane radicals into tertiary and is consistent with the experimental data. The regioselectivity of the process is linearly related to the concentration of hydrogen chloride, so that the rate constant for the addition of primary 2,3-dimethylbutane radical to 3,4-dichloro-2,5-dihydrofuran-2,5-dione may be estimated. Effective procedures for the synthesis of 3-chloro-4-(2,3-dimethylbut-2-yl)-, 3-chloro-4-cyclohexyl-, and 3,4-dicyclohexyl-2,5-dihydrofuran-2,5-diones have been proposed.