REARRANGEMENT OF THE CARBON SKELETON OF PERFLUORINATED 1-ISOPROPYL-, 1-METHYL-1-ISOPROPYL-, AND 1-METHYL-2-ISOPROPYLBENZOCYCLOBUTENES BY THE ACTION OF ANTIMONY PENTAFLUORIDE

Article abstract of DOI:10.1007/BF00866598

Perfluorinated 1-isopropyl-, 1-methyl-1-isopropyl-, and 1-methyl-2-isopropylbenzocyclobutenes isomerize under the influence of antimony pentafluoride to perfluorinated alkylstyrenes and alkylindans.The process may be accompanied by dealkylation and also by fluorination and defluorination of the products.With antimony pentafluoride at 50 deg C perfluoro-1-methyl-1-isopropylbenzocyclobutene gives perfluoro-α,β,β,o-tetramethylstyrene, which izomerizes under the influence of antimony pentafluoride at 130 deg C into perfluoro-1,2,2-trimethylindan, and the latter forms perfluoro-2,3-dimethylindene under the reaction conditions.Perfluoro-1-methyl-2-isopropylbenzocyclobutene is not changed in the presence of antimony pentafluoride at 50 deg C but isomerizes to perfluoro-1-isopropylindan at 90 deg C.The latter is transformed under these conditions into the above-mentioned tetramethylstyrene.Perfluoro-1-isopropylbenzocyclobutene does not react with antimony pentafluoride at 130 deg C, but at 170 deg C it gives a mixture of perfluorinated 2,2-dimethylindan, 2,3-dimethylindene, 2,3-dimethyl-4,5,6,7-tetrahydroindene, and 2-isobutyltoluene, which is converted into perfluoro-o-xylene under the reaction conditions. Keywords: Perfluoroalkylbenzocyclobutenes, perfluoroalkylstyrenes, perfluoroalkylindans, antimony pentafluoride, cationoid skeleton transformations.