Skeletal transformations of perfluoro-1-ethyl-1-phenylbenzocyclobutene in the reaction with antimony pentafluoride

Interaction of perfluoro-1-ethyl-1-phenylbenzocyclobutene with SbF5 at room temperature gives, after treatment of the reaction mixture with H2O, perfluoro-4-[1-(2-methylphenyl)propylidene]cyclohexa-2,5-dienone as a main product. The reaction at 90-95 °C leads, after treatment with H2O, to a mixture of perfluorinated 9-ethyl-9-methyl-1,2,3,4-tetrahydro-9H-fluorene, 9-ethyl-4a-methyl-4,4a-dihydrofluoren-1-one, 3-ethyl-3-phenylphthalide, 1-hydroxy-2-methyl-1-phenylindan, 3-methyl-2-phenylindenone and small amounts of other products.