Potassium permanganate solid support

Primary and secondary alcohols are oxidized slowly at low temperatures by benzyltriethylammonium permanganate in dichloromethane primary alcohols produce methylene esters (60-70%), resulting from reaction of the initially formed carboxylate anion with the solvent, with minor amounts of the chloromethyl esters and the carboxylic acids. Secondary alcohols are oxidized (75-95%) to ketones [34] the yields compare favourably with those obtained using potassium permanganate on a solid support. 1,5-Diols are oxidized by potassium permanganate under phase-transfer catalytic conditions to yield 8,8-disubstituted-8-valerolactones [35] (Scheme 10.1). 

Trans -substituted diarylalkenes undergo oxidative cleavage upon treatment by potassium permanganate in the presence of moist alumina as a solid support (equation 32)158. Under the same conditions, cyclic alkenes, with medium-sized rings, give acyclic dialdehydes (equation 33). 

Syn hydroxyladon is most commonly performed using osmium tetroxide or potassium permanganate, and addition usually occurs hx)mrhe less hindered side of the double bond in the absence of other directing effects. With Aese reagents, the steieospecificity of syn addition results from formation of cyclic ester intermediates. Support for these arises from isolation of solid addition complexes (1) on reaction of... 

The theory that the oxygenated recoil species are formed in reactions between recoil atoms and surrounding oxyanions or dislodged oxygens is supported by the results of mixed crystal experiments. Mixed crystals (solid solutions) of potassium chromate in potassium sulfate [35) and fluoberyllate (50), and potassium permanganate in potassium perchlorate (67) have been investigated. The results are given in Table II. These... 

The role of the supports in the reactions just described is not clear. Even less clear is the function of copper sulfate pentahydrate, in the presence of which oxidations with solid potassium permanganate result in excellent yields of ketones. Traces of water are essential. Primary alcohols, on the other hand, give poor yields of aldehydes and acids [844 (equation 255). 

The ester function is in general unaffected by most of the Nef reaction conditions. Of particular interest are those reactions using methanol or ethanol as the solvent for hydrolysis." " It is worth noting that treatment of a nitronate salt by sulfuric acid in absolute methanol at -10 °C yields dimethyl acetal, i.e. a protected form of the aldehyde. For solid phase hydrolysis, silica gel" " or potassium permanganate supported on silica gel " are remarkably efficient reagents, especially for small scale reactions. 

Potassium permanganate. 13, 258-259 14, 267 15,273-274 18,301 19,277-278 Oxidations. Well-known oxidation processes have been modified by ultrasound assistance, dispersion of KlVInO on solid supports such as alumina, " zeolite, and kieselguhr. ... 

Limitations in the use of potassium permanganate and similar oxidizing agents [102-104] have already been mentioned in Section 2.2.2.4. The immobihzation of metallic reagents on solid supports has addressed some of these Hmitations and... 

Supported reagent. One limitation to potassium permanganate is the limited solubility in organic solvents. Solubilization with a crown ether is one solution (4,143) another is impregnation on an inorganic solid support such as a molecular sieve, silica gel, and certain clays. Although the factors responsible for the enhanced reactivity of this form of KMn04 are not understood, such materials are useful for oxidation. ... 

Several references have appeared on the use of solid-phase oxidants. Solid potassium permanganate-copper sulphate mixtures oxidize secondary alcohols to ketones in high yield, and pyridinium chromate or chromic acid on silica gel are described as convenient off-the-shelf reagents for oxidation of both primary and secondary alcohols. Anhydrous chromium trioxide-celite effects similar transformations only when ether is present as co-solvent. An excellent review, with over 400 references, on supported oxidants covers the use of silver carbonate-celite, chromium trioxide-pyridine-celite, ozone-silica, chromyl chloride-silica, chromium trioxide-graphite, manganese dioxide-carbon, and potassium permanganate-molecular sieve. 

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