ACYL NITROXIDES .3. REACTIONS WITH PHENOLS, ALCOHOLS, ETHERS, AND SULFIDES

Many monohydric phenols are efficiently oxidised to quinones by acyl t-butyl nitroxides in organic solvents. The reaction, which parallels the Teuber oxidation, fails with phenol itself and with some other simple phenols. Diphenylamine gives N-phenyl-p-benzoquinone imine. t-Butyl 3,5-dinitrobenzoyl nitroxide is the nitroxide of choice for selectively oxidising allylic and benzylic alcohols to the corresponding aldehydes and ketones. Saturated secondary alcohols may also be oxidised to ketones, but more slowly. The nitroxides slowly effect α-substitution in ethers; a similar but apparently more rapid, reaction occurs with sulphides.