Oxoammonium Ions in Alcohol Oxidation

In addition a very useful and frequently applied method in the fine chemical industry to convert alcohols into the corresponding carbonyl compounds is the use of oxoammonium salts as oxidants [15]. These are very selective oxidants for alcohols, which operate under mild conditions and tolerate a large variety of functional groups. 

Alternatively TEMPO can be reoxidized by metal salts or enzyme. In one approach a heteropolyacid, which is a known redox catalyst, was able to generate oxoammonium ions in situ with 2 atm of molecular oxygen at 100 °C [223]. In the other approach, a combination of manganese and cobalt (5 mol%) was able to generate oxoammonium ions under acidic conditions at 40 °C [224]. Results for both methods are compared in Table 4.9. Although these conditions are still open to improvement both processes use molecular oxygen as the ultimate oxidant, are chlorine free and therefore valuable examples of progress in this area. Alternative Ru and Cu/TEMPO systems, where the mechanism is me- 

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