(A) new method for the oxidative conversion of nitro groups into carbonyls using potassium superoxide

Abstract

It was found that potassium superoxide converted efficiently nitro compounds to the corresponding carbonyl compounds. In addition, it oxidized nitro functional group chemoselectively. Nitro compounds with other functional groups are converted the carbonyls without affecting other functionallities. For example, 1-nitro-2-(phenylthio) cyclohexane was converted into 2-(phenylthio) cyclohexanone in a good yield. The sulfide moiety was not oxidized to the sulfoxide nor the sulfone. When the previous methods are used for the conversion of nitro compounds to carbonyls, the formation of nitroate anion by approriate base is required. This system does not need a base because potassim superoxide plays a act of not only a oxidant, but also a base. The reaction appears to be proceeded via the formation of nitroate anion, followed by the cleavage of carbon-nitrogen double bond to carbonyl group. Bisdiphenylphosphinic peroxide reacted with sulfides containing a electron-rich olefin to give the corresponding sulfoxides in exellent yields without the formation of epoxides nor sulfones. It shows a good chemoselectivity in the oxidation of sulfides having a double bond to the sulfoxides.