Perbenzoic acid oxidant

Baeyer-Villiger oxidation (perbenzoic acid) of some 5a-cholestan-6-ones, including the 3a,5-cycIo-analogue, gave the 6-oxa-B-homocholestan-7-ones, with exclusive migration of C(5) rather than C(7) in each case cf. Beckmann Rearrangements, p. 281). 

Perbenzoic acid is used for the conversion of ethylenic compounds into oxides ... 

Ethylenic compounds when oxidised with perbenzoic acid or perphthalic acid in chloroform solution yield epoxides (or oxiranes). This Is sometimes known as the Prileschajew epoxidation reaction. Thus pyrene affords styrene oxide (or 2-plienyloxirane) ... 

The methochloride of (IX) occurs in two forms, identical with the a-and )S-forms of Modihydrocr3T)topine chloride (X). The two chlorides were converted into the two anhydrodihydrocryptopines A and B (p. 297). Of these the A base was oxidised by perbenzoic acid to the amine oxide (XI), m.p. 135° dec.), and this on heating with acetic and hydrochloric acids passed into cryptopine (XII), m.p. 220-1°, identical in all respects with the natural alkaloid. 

The most common method of epoxidation is the reaction of olefins with per-acids. For over twenty years, perbenzoic acid and monoperphthalic acid have been the most frequently used reagents. Recently, m-chloroperbenzoic acid has proved to be an equally efficient reagent which is commercially available (Aldrich Chemicals). The general electrophilic addition mechanism of the peracid-olefin reaction is currently believed to involve either an intra-molecularly bonded spiro species (1) or a 1,3-dipolar adduct of a carbonyl oxide, cf. (2). The electrophilic addition reaction is sensitive to steric effects. 

In a typical Knof procedure, 3jS-hydroxyandrost-5-en-17-one acetate is epoxidized with perbenzoic acid (or m-chloroperbenzoic acid ) to a mixture of 5a,6a- and 5)5,6)5-epoxides (75) in 99 % yield. Subsequent oxidation with aqueous chromium trioxide in methyl ethyl ketone affords the 5a-hydroxy-6-ketone (76) in 89% yield. Baeyer-Villiger oxidation of the hydroxy ketone (76) with perbenzoic acid (or w-chloroperbenzoic acid ) gives keto acid (77) in 96% yield as a complex with benzoic acid. The benzoic acid can be removed by sublimation or, more conveniently, by treating the complex with benzoyl chloride and pyridine to give the easily isolated )5-lactone (70) in 40% yield. As described in section III-A, pyrolysis of j5-lactone (70) affords A -B-norsteroid (71). Knof used this reaction sequence to prepare 3)5-hydroxy-B-norandrost-5-en-17-one acetate, B-noran-... 

By means of perbenzoic acid oxidation, a bicyclic oxazirane (233,234) (152) is formed from 5,5-dimethyl-4-phenyl-/l -pyrroline (151). 

Reactions of benzoylperoxide with morpholinocyclohexene and morpho-linocyclopentene furnished the corresponding a-benzoyloxyketones in modest yields (480,481). This oxidation has also been applied to some vinylogous amides (482), and the expected faster rate of reaction of the enamine system as compared with enamides has been noted in derivatives of 20-ketosteroids, in reactions with perbenzoic acid (59,483). 

Reaction of j8-carboline derivatives with hydrogen peroxide or perbenzoic acid and of S-carboline with peracetic acid yields the corresponding yr-A-oxide (e.g. 280). 

Oxidation of 4-methylquinoxalin-3-one 2-carboxy-fV -methylamlide (45) with hydrogen peroxide and acetic acid furnishes the 1-oxide but, on removal of either or both of the fV-raethyl groups (giving 46, 47, or 48), oxidation with hydrogen peroxide or with peracetic or perbenzoic acid results in the removal of the carboxyamide groups and the formation of a quinoxaline-2,3-dione. ... 

A. Perbenzoic Acid Oxidation of Ketones General Procedure (10)... 

Similarly, the most common method of preparing the substituted, fully unsaturated thiolane system, e.g. thiophene dioxides, is by direct oxidation of the readily available substituted thiophenes with hydrogen peroxide, perbenzoic acid and m-chloroperbenzoic acid280 283. Alternatively, thiophene dioxides are conveniently prepared via the double elimination methodology280 305 illustrated in equation 117. 

Aromatic peracids are frequently used for the oxidation of sulphoxides to sulphones. The most common peracids of this type are perbenzoic acid and mefa-chloroperbenzoic acid, although many others have been employed. 

Optically stable racemic phosphines have been oxidized with one half equivalents of optically active peracid. The remaining phosphine, oxidized with perbenzoic acid, showed low optical activity, but the phosphine oxides obtained in the asymmetric oxidation were optically inactive. ... 

The deoxygenation of peroxycarbonates (53) with phosphines and phosphites has been examined. Reaction with phosphites favours pyrocarbonate formation (Path A) whilst phosphines favour carbonate formation (Path B). Secondary phosphine oxides are oxidized to phosphinic acids by perbenzoic acid. The kinetics of the deoxygenation of hydroperoxides by triphenylphosphine have been examined and the reaction shown to be catalysed by strong acids. ... 

A chemical method developed by Kolthoff and Lee for quantitatively determining the proportion of 1,4 and 1,2 units in a polybutadiene involves measurement of the rate of oxidation of the residual double bond by perbenzoic acid. 

Oxidation of thiirane and thiirene oxides to the dioxides is the best method to obtain the sulfones. Indeed, in the acyclic, or large-ring systems, the sequence sulfide- sulfoxide - sulfone is by far the easiest method to prepare sulfoxides and sulfones. The situation is different in the three-membered ring series Thus, oxidation of thiiranes to the oxides by either perbenzoic acid or m-chloroperbenzoic acid under mild conditions affords the corresponding thiirane sulfoxides in almost quantitative yield - . However, further... 

Electron-donating groups in the para position of the perbenzoic acid tend to decrease the rate of reaction . The reverse seems to be true when these groups are present in a 4,4 -disubstituted diaryl sulphoxide. The effect of ring size on the oxidation of cyclic sulphoxides is apparently very small in dioxane-water solution under either acidic or basic conditions . This suggests that no major hybridisation change occurs for the sulphur atom in going to the transition state. 

---