Butylperoxy radicals phenols

Howard, J.A. and E. Furimsky. 1973. Arrhenius parameters for reactions of tert-butylperoxy radicals with some hindered phenols and amines. Can.. Chem. 51 3738-3745. 

The spectra of a large number of aryloxy radicals have been obtained by the one-electron oxidation of the corresponding phenols by metals in high-valence states. The more stable radicals, such as 2,4,6-tri-t-butylphenoxy (21), may be examined in a static system Becconsall et al. (1960) have used lead dioxide as the oxidant. The observation of less stable radicals, such as phenoxy, necessitates the use of a flow system Stone and Waters (1964a) have employed ceric ion as the oxidant and a relatively simple flow technique. Thomas (1966) has used the same method to obtain the t-butylperoxy radical from t-butyl hydroperoxide. 

The substrate scope and mechanism of Rh2(cap)4-catalysed TBHP oxidation of phenol and aniline was discussed. The rate of oxidation of para-substituted phenols to 4-(f-butyldioxy)cyclohexadien ones increased significantly in aromatic hydrocarbon solvents. Comparative results with RuCl2(PPh3) and Cul were provided. The results were consistent with hydrogen atom abstraction by the f-butyl peroxy radical followed by combination of the phenoxy and the f-butylperoxy radicals. Under similar reaction conditions,para-substituted anilines were oxidized to the corresponding nitroarenes, and primary amines were oxidized to carbonyl compounds in moderate to good yields. ... 

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