Chlorination and decarboxylation of (heptafluoronaphthalen-2-yl)acetic acid. Synthesis of 2-(dichloromethyl)- and 2-(difluoromethyl)heptafluoronaphthalenes

Decarboxylation of (heptafluoronaphthalen-2-yl)acetic acid in DMF in the presence of NaHCO₃ gave 2-methylheptafluoronaphthalene, and treatment with PCl₅ on heating afforded dichloro(heptafluoronaphthalen-2-yl)acetic acid. Decarboxylation of the latter in DMF led to the formation of 2-(dichloromethyl)-heptafluoronaphthalene which was converted to 2-(difluoromethyl)heptafluoronaphthalene by heating with cesium fluoride.