Introduction TEMPO (2,2,6,6-Tetramethyl-1-piperidinyloxy radical), as an oxidizing reagent, is the most representative member of the generally called nitroxyl radical oxidant family. They are characterized as weak oxidants that are stable, and soluble in both polar and apolar solvents. However, the radical can be oxidized to form the corresponding oxoammonium salt that is capable of oxidizing many organic functional groups. This oxidized species (Scheme 1) can be generated separately from the reaction mixture or, more interestingly, in situ, allowing a catalytic cycle.
Some reviews can be found in the literature,
[1
