Oxammonium salts, oxidation

Oxammonium salts 1 have been used extensively either in stoichiometric or in catalytic amounts12 for the oxidation of primary and secondary alcohols to the corresponding carbonyl derivatives. 

Oxammonium salt 1, the effective oxidant species, is continuously generated from nitroxyl radical 2 by hypochlorous acid in the organic phase. Radical 2 is one of... 

Preparation of Tetramethylpiperidine-l-oxammonium Salts and Their Use as Oxidants Merbouh, N. Bobbitt, J.M. BrUckner, C. Org. Prep. Proceed. Int. 2004,36,1. 

Oxammonium salts such as 81 are new and powerful oxidizing agents for the selective oxidation of alcohols to aldehydes or ketones. 28 Such salts can be generated catalytically from small amounts of a nitro-xide in the presence of a secondary oxidation procedure, either chemical or electrochemical,. 29 or with two equivalents of acid and 2 equivalents of a nitroxide. When 81 was mixed with acetylenic alcohol 82 in dichloromethane, aldehyde 83 was isolated in 93% yield. The reaction can be monitored as the initial yellow slurry changes to a white slurry and the presence of unreacted oxidant can be checked with starch. 3l It is not necessary to use anhydrous conditions, and it was discovered that the rate of reaction was enhanced by the presence of silica gel. This reagent is compatible for the mild oxidation of many alcohols, including aliphatic primary and secondary as well as allylic and benzylic alcohols. 

It is well known that tertiary ally lie alcohols such as 21 can be oxidized to the corresponding enone 23 with chromium reagents. Yoshiharu Iwabuchi of Tohoku University observed (J. Org. Chem. 2008, 73, 4750) that the oxammonium salt 22 derived from TEMPO effected the same transformation. David E. Richardson of the University of Florida found (Tetrahedron Lett. 2008, 49, 1071) that could be used to oxidize N-methyhnorpholine in situ to the N-oxide, that in turn reoxidized catalytic OsO. In the presence of the Sharpless ligand, the dihydroxylation proceeded withhighee. This approach could offer cost and waste stream advantages over currently used oxidants. 

Oxalic Acid, Diammonium Salt Oxalic Acid Dinitrile Oxalic Acid, Ferrous Salt Oxalonitrile Oxammonium Sulfate 3-Oxa-1,5-Pentanediol 2-Oxetanone Oxides of Nitrogen Oxirane... 

The triflate salt of 4-hydroxy-2,2,6,6-tetramethylpiperidinium M-oxide, R2NO, an oxammonium ion, is reduced by alcohols (giving ketones and aldehydes) the immediate product of the reduction is the hydroxylamine, R2NOH, but its further... 

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