Cerium IV and Other Oxidizing Agents

Among the various cerium(IV) complexes, cerium(IV) ammonium nitrate (CAN) is the most important oxidant in organic synthesis, since it is sufficiently stable in different solvents and is commercially available. Besides its propensity of introducing and removing protecting groups via single-electron transfer or Lewis acid catalysis 

This methodology can be extended to various glycals 16, and the reactions exhibit high stereoselectivities. 

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It is a commonplace to say that there has been explosive growth in the use of lanthanides in organic chemistry. For many years, the use of cerium(iv) compounds as oxidants was widespread, but more recently a whole range of other compounds have made their appearance. Thus samarium(ii) compounds are now routinely used as one-electron reducing agents and the use of trifluoromethanesulfonate ( triflate ) salts of scandium and the lanthanides as water-soluble Lewis acid catalysts is widespread. Beta-diketonate complexes and alkoxides have also come into use there are even applications of mischmetal in organic synthesis. 

Anthranilic acid reagent (NH2-C(,H COOH) cerium(IV) oxidizes anthranilic acid to a brown compound. Cerium(III) does not react and must be oxidized first with lead dioxide and concentrated nitric acid to cerium(IV) other oxidizing agents cannot be used, since they react with the anthranilic acid. Iron(III) ions inhibit the test and must be masked by the addition of phosphoric acid. The ions of gold and vanadium, as well as chromate ion, react similarly and therefore interfere. Reducing agents must be absent. 

There is a number of investigations where potassium permanganate was replaced by other oxidizing agents and few will be mentioned here. Decomposition products of citric acid in the oxidation with cerium(IV) salts [211-217] are according to Ajl et al. [213] acetone and carbon dioxide... 

The first step in the GC determination of carbon and hydrogen is quantitative oxidation of the sample organic compounds, usually with a catalyst. Copper oxide is commonly used, but the reaction is relatively slow and elevated temperatures of about 900°C are required. With silver permanganate the reaction temperature is reduced to 550°C [34, 35] and with cobalt oxide to 750°C [36, 37] both compounds provide a shorter oxidation time. Other catalytic oxidizing agents, such as nickel oxide [38, 39] and cerium(IV) oxide [40], have been found promising. Platinum can also be used, especially when it is necessary to avoid the retention of any oxidation products by the solid catalyst. 

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