Synthesis and skeletal rearrangements of perfluorinated 4-alkyl- and 4-phenyl-tetralin-1-ones under the action of antimony pentafluoride

Heating of perfluorinated 1-methyl- and 1-ethyltetralins with SiO2 in an SbF5 medium at 100 °C results in perfluoro-4-alkyltetralin-1-ones formation. Perfluoro-4-methyltetralin-1-one, under the action of SbF5 at 180 °C with subsequent treatment of the reaction mixture with water, is converted to perfluoro-3,3-dimethylindan-1-one and perfluoro-3,4-dimethylisochromen-1-one. Perfluoro-4-ethyltetralin-1-one, under similar conditions, forms perfluoro-3-ethyl-3-methylindan-1-one, perfluoro-4-ethyl-3-methylisochromen-1-one and perfluoro-2-methyltetralin. Reaction of perfluorotetralin-1-one with pentafluorobenzene in the presence of SbF5 at 50–55 °C leads to the formation of perfluoro-4-phenyltetralin-1-one, which under the action of SbF5 at 75 °C isomerizes into perfluoro-3-methyl-3-phenylindan-1-one. Heating of the latter with SbF5 at 75–95 °C gives, after treatment of the reaction mixture with water, perfluoro-2-(2-methylphenyl)-3-phenylpropenoic acid and perfluoro-4-methyl-3-phenylisochromen-1-one.