Formation of Polyfluoro-1-ethylfluorenes in the Reaction of Perfluoropropylbenzene with Tetrafluorobenzenes in an SbF5 Medium

The interaction of perfluoropropylbenzene with 1,2,3,4-tetrafluorobenzene or 1,2,4,5-tetrafluorobenzene in an SbF5 medium at r.t. yields corresponding 1-(tetrafluorophenyl)perfluoro-1-phenylpropanes, which undergo cyclization into perfluoro-9-ethylfluorene or 1,2,3,4,5,7,8,9-octafluoro-9-(pentafluoroethyl)fluorene along with 1,2,3,4-tetrahydro-9H-fluorenes under the reaction conditions. The reaction of perfluoropropylbenzene with 1,2,3,5-tetrafluorobenzene under the same conditions leads to the formation of 1-(2,3,4,6-tetrafluorophenyl) perfluoro-1-phenylpropane, which does not give cyclization products at 50-55 degrees C.