Reactions of 1,2,4,5-Tetrafluoro-3-(perfluoropropyl)benzene with 1,2,3,4- and 1,2,4,5-Tetrafluorobenzenes in an SbF5 Medium

Abstract The reaction of 1,2,4,5-tetrafluoro-3-(perfluoropropyl)benzene with 1,2,3,4-tetrafluorobenzene in an SbF5 medium afforded a mixture of 1,2,3,4,5,7,8,9-octafluoro-9-(pentafluoroethyl)fluorene and 1,2,4,5,6,7,9-heptafluoro-9-(pentafluoroethyl)fluorene with a considerable predominance of the former. In a similar reaction with 1,2,4,5-tetrafluorobenzene at room temperature, 1,2,4,5,7,8,9-heptafluoro-9-(pentafluoroethyl)fluorene was formed in low yield, whereas conducting the reaction with an excess of the tetrafluorobenzene upon heating afforded 1,2,4,5,7,8-hexafluoro-9-(pentafluoroethyl)-9-(2,3,5,6-tetrafluorophenyl)fluorene in 52% yield. The hindered rotation of the tetrafluorophenyl group in this ethylphenylfluorene was studied.