Synthesis of α-Fluoro-α-nitroarylacetates via Vicarious Nucleophilic Substitution of Hydrogen.

Readily available ethyl chlorofluoroacetate, when treated with a strong base, forms an α-chloro-α-fluorocarbanion that adds to nitroarenes at a position ortho or para to the nitro group with formation of anionic σ adducts. Subsequent base-induced β-elimination of HCl proceeds selectively to give nitrobenzylic α-fluorocarbanions and, upon protonation, ethyl α-fluoro-α-nitroarylacetates.