Reaction of nitroalkanes with polyfluoroaromatic compounds

Nitromethane and nitroethane in the presence of DBU attack preferentially the para position of pentafluorobenzonitrile and methyl pentafluorobenzoate to give the addition products in good yield. The resulting nitro compounds can be converted to tetrafluorotoluene or ethyl benzene derivatives by tri-n-butyltin hydride. TiCl3 solution neatly transforms the nitroethyl compounds into corresponding ketones. With a base, the nitro compounds can be used to extend chain length using Michael acceptors like ethyl acrylate and acrylonitrile.

Graphical abstractNitromethane and nitroethane in the presence of a base replaces predominantly para fluorine from pentafluorobenzonitrile and methyl pentafluorobenzoate to provide the corresponding nitrocompounds. These undergo typical reactions such as reduction with TBTH, oxidation with TiCl3 and Michael addition with ethyl acrylate and acrylonitrile.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Nucleophilic substitution of nitroalkyl carbanion occurs at para position of pentafluorobenzonitrile and methyl pentafluorobenzoate. ► The nitro compounds thus formed undergo tin hydride reduction and Nef reaction to give valuable products. ► In presence of base, the nitro compounds add on to Michael acceptors.