MECHANISM OF ARENE HYDROXYLATION BY VANADIUM PICOLINATO PEROXO COMPLEXES

The mechanism of the reaction of VO(O-2)PIC(H2O)(2) (PIC = picolinic a cid anion) with benzene and substituted benzenes in CH3CN, affording t he corresponding phenols together with dioxygen, has been further inve stigated. The reaction is a radical chain process whose initiation pro duces the actual oxidant which may be described as a radical anion der ived from the peroxovanadium complex, possessing, however, a marked el ectrophilic character. In the propagation steps such species react eit her with the original peroxo complex yielding dioxygen or with the aro matic substrates affording phenols via the formation of an intermediat e.