Donald G. Lee

Solvent free permanganate oxidations

Abstract The oxidations of organic compounds by permanganate under solvent free conditions have been studied. Thiols and primary aromatic amines undergo oxidative coupling reactions to give disulfides and diazenes, respectively, sulfides are oxidized to sulfones, primary and secondary alcohols are converted to aldehydes and ketones, 1,4-diols and cyclic ethers give lactones and arenes are oxidized to the corresponding α-ketones. The experimental procedure is simple and the products are easily isolated in good yields.

Selective oxidation of alkylarenes in dry media with potassium permanganate supported on montmorillonite K10

Abstract— The solvent-free oxidation of alkylarenes with KMnO 4 supported on montmorillonite K10 is reported. The beneficialeffects of microwave and ultrasound irradiation on the reactions is described.

Potassium Permanganate Oxidation of Organic Compounds

Abstract It has been discovered that potassium permanganate is an effective heterogeneous oxidant, even without resorting to the use of a solid support, if acetonitrile is employed as the solvent. Primary benzylic and secondary alcohols are converted to the corresponding aldehydes and ketones, alkyl arenes are oxidized to the corresponding α‐ketones in good yields using this procedure, and both alkyl and aryl sulfides are smoothly converted to the corresponding sulfones, also in excellent yields. When methylene chloride is used as the solvent, instead of acetonitile, the yields of aldehydes, ketones, α‐ketones, and sulfones are reduced. However, the oxidation of thiols to disulfides proceeds satisfactorily when methylene chloride is the solvent.

Lewis acid assisted permanganate oxidations

Lewis acids combine with permanganate in acetone solutions to form a complex that has enhanced oxidizing capabilities. The use of Lewis acids under these conditions to promote permanganate oxidations is superior to the use of Bronsted acids because the latter promote enolization of the solvent and subsequent unproductive reduction of the oxidant. The products obtained from a variety of alkenes, alkynes, arenes, sulfides, alcohols and ethers have been identified and probable reaction mechanisms proposed.

Selective oxidation of unsaturated alcohols by potassium permanganate adsorbed on solid supports

Abstract Potassium permanganate adsorbed on solid supports can be used to oxidize unsaturated secondary alcohols to the corresponding ketones without degradation of the carbon—carbon double bonds.

Ion Exchange Catalysis in Oxidation of Organic Compounds with KMnO4

Abstract The oxidation of organic compounds under ion exchange resin (IER) catalysis by KMnO4 has been studied in CH2Cl2 under reflux conditions. Secondary aliphatic and aromatic alcohols are converted to ketones, alkyl arenes and sulfides oxidized to corresponding ketones and sulfones, respectively, and thiols undergo oxidative coupling reactions to give disulfides. The experimental procedure is simple and products are easily isolated in good yields.

3.8 – Cleavage Reactions

Oxidative cleavage is a procedure often employed to degrade large compounds or to introduce different functionality into complex molecules. A number of reagents have been used for this purpose with generally good success.1–4

MECHANISMS FOR THE OXIDATION OF PARA-SUBSTITUTED BENZYL ALCOHOLS AND BENZYL ETHERS BY PERMANGANATE

Abstract Permanganate, solubilized in methylene chloride with the aid of a phase transfer agent, oxidizes benzyl alcohol to benzaldehyde and benzyl ethers to benzoate esters. Although the rate of oxidation of the ether is about an order of magnitude slower than alcohol oxidation, both respond in an identical way to the unique effects caused by introduction of substituents into the ring. In addition, primary kinetic isotope effects are observed for both reactions. Because of these similarities, it is proposed that benzyl alcohols and benzyl ethers are oxidized by similar mechanisms, the difference in rate being ascribed to steric effects.

Oxidation of Organic Compounds by Potassium Permanganate Supported on Montmorillonite K10

Abstract The oxidation of organic compounds by potassium permanganate supported on Montmorillonite K10 has been studied under solvent‐free conditions and the results compared with those from corresponding reactions where the reductants are dissolved in methylene chloride. Under both sets of conditions, primary benzylic and secondary alcohols are converted to aldehydes and ketones respectively, sulfides are oxidized to sulfones, and thiols undergo oxidative coupling to give disulfides. Surprisingly, reaction times under solvent‐free conditions are shorter than those observed when the reductants are dissolved in a solvent.

Solvent Free Ion Exchange Catalysis in the Oxidation of Organic Compounds with Sodium Bromate

Abstract The oxidation of organic compounds under solvent free ion exchange resin (IER) catalysis by sodium bromate has been studied at room temperature. Primary benzylic and secondary alcohols are converted to aldehydes and ketones and alkylarenes are oxidized to the corresponding α-ketones. The experimental procedure is simple and products are easily isolated in high yields at room temperature.