Phenylation Reaction of α-Acylnitromethanes To Give 1,2-Diketone Monooximes: Involvement of Carbon Electrophile at the Position α to the Nitro Group

Abstract

The generality and the effects of substituents on phe­nylation reactions of α-acylnitromethanes catalyzed by trifluoromethanesulfonic acid have been studied. α-Aroylnitromethanes afforded benzil monooximes in good yield. In the case of aliphatic α-acylnitromethane, a similar phenylation reaction proceeded, but the yield of the phenylated 1,2-dione monooxime was low. These phenylation reactions represent examples of the generation of carbocation electrophiles at the α-position of a nitro group.

α-ketonitromethane - 1,2-dione monooxime - electrophilic aromatic substitutions - umpolung - protonation

References

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<A NAME="RF13909SS-9">9</A>

Detection of ^¹H-NOE between the CH₃ group and the aromatic ortho-protons supported the assignment of the E-geometry of the olefin of 6b.

<A NAME="RF13909SS-10">10</A>

The reaction of 2a also proceeded with substituted benzenes, p-xylene and anisole, to give the corresponding oximes in comparable yields (see ref 3).