An unknown ring expansion of halogenated benzocycloalkenes has been found when perfluoro-1-methylbenzocyclobutene (I) was reacted with Lewis acids. Perfluoroindane was formed under heating of compound (I) with SbF 5 . The interaction of compound (1) with AlBr 3 (25–30°C) depends on the amounts of AlBr 3 and gives compounds (II) or (IV), or a mixture of compounds (II), (III) and (IV). Some of the investigated transformations are shown on the ...
