Peroxyacetic acid hydroxylation

Radical hydroxylation of hydrocarbons by autooxidation yields alcohols (major products), ketones, and acids (minor products). Cyclohexanol, for example, is formed in 90% yield from cyclohexane and peroxyacetic acid (275). The high -ol/-one ratio at low conversions can sometimes be used as a partial diagnostic tool to distinguish between the radical and electrophilic pathways. The predominant reaction of electrophilic radicals, such as HO, ROO, and CH 3 is H-atom abstraction from reactants (S-H) or peracids, as exemplified by the following ... 

Peroxyacetic acid oxidation is similar to the peroxytrifluoroacetic acid (Deno) oxidation (28). These peroxide systems are reported to selectively oxidize the aromatic portions of molecules while leaving aliphatic portions intact (29). Peroxyacetic acid will oxidize aromatic units to phenolic units via hydroxylation. These phenolic moieties will oxidize rapidly to ortho and para quinones, the latter of which are unstable are undergo ring fission to form diene carboxylic acids (30). 

Direct anti hydroxylation of an alkene (without isolation of the epoxide intermediate) is possible by using an acidic aqueous solution of a peroxyacid. As soon as the epoxide is formed, it hydrolyzes to the glycol. Peroxyacetic acid (CH3CO3H) and peroxyformic acid (HCO3H) are often used for the anti hydroxylation of alkenes. 

The most important applications of peroxyacetic acid are the epoxi-dation [250, 251, 252, 254, 257, 258] and anti hydroxylation of double bonds [241, 252, the Dakin reaction of aldehydes [259, the Baeyer-Villiger reaction of ketones [148, 254, 258, 260, 261, 262] the oxidation of primary amines to nitroso [iJi] or nitrocompounds [253], of tertiary amines to amine oxides [i58, 263], of sulfides to sulfoxides and sulfones [264, 265], and of iodo compounds to iodoso or iodoxy compounds [266, 267] the degradation of alkynes [268] and diketones [269, 270, 271] to carboxylic acids and the oxidative opening of aromatic rings to aromatic dicarboxylic acids [256, 272, 271, 272,273, 274]. Occasionally, peroxyacetic acid is used for the dehydrogenation [275] and oxidation of aromatic compounds to quinones [249], of alcohols to ketones [276], of aldehyde acetals to carboxylic acids [277], and of lactams to imides [225,255]. The last two reactions are carried out in the presence of manganese salts. The oxidation of alcohols to ketones is catalyzed by chromium trioxide, and the role of peroxyacetic acid is to reoxidize the trivalent chromium [276]. 

The trioxolane was also shown to effect epoxidation of olefins86). This was differentiated from the peracid pathway by generating the intermediate at — 100 °C. Warming this system to — 50 °C in the presence of olefins resulted in the formation of epoxides. The corresponding experiment with peroxyacetic acid at — SO °C showed no epoxidation of the olefins. The trioxolane was also shown to effect hydroxylation of tert-butylphenol to tert-butylcatechol, in agreement with an oxene transfer mechanism. 

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