Synthesis of Cyclic Peroxides by Chemo-and Regioselective Peroxidation of Dienes with Co(II)/O_2/Et_3SiH

摘要

In the competitive peroxidation of mixtures of two alkenes with Co(II)/O_2/Et_3SiH,it was found that the relative reactivities of the alkene substrates are influenced by three major factors:.(1)relative stability of the intermediate carbon-centered radical formed by the reaction of the alkene with HCo(III)complex,(2)steric effects around the C=C double bond,and(3)electronic factors associated with the C=C double bond.Consistent with results from simple alkenes,the chemo-and regioselective peroxidation of dienes was also realized.Depending on the diene structure,the product included not only the expected acyclic unsaturated triethylsilyl peroxides but also 1,2-dioxolane and 1,2-dioxane derivatives via intramolecular cyclization of the unsaturated peroxy radical intermediates.