The alicyclic ring cleavage and other transformations of perfluorinated 1-alkyl-, 1,1- and 1,2-dialkyl-benzocyclobutenes in the system Br 2SbF 5

• Published in: Journal of fluorine chemistry Vol. 77; no. 2; pp. 133 - 137
• Main Authors: Karpov, V.M., Mezhenkova, T.V., Platonov, V.E.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 1996
• Subjects: Alicyclic ring cleavage; Br 2SbF 5 system; Mass spectrometry; NMR spectroscopy; Perfluoroalkyl benzocyclobutenes; Perfluorodialkylbenzocyclobutenes; Br 2SbF 5 system; Perfluorodialkylbenzocyclobutenes; Perfluoroalkyl benzocyclobutenes; NMR spectroscopy; Mass spectrometry; Alicyclic ring cleavage
• ISSN: 0022-1139; 1873-3328
• DOI: 10.1016/0022-1139(96)03390-8

In the reactions of perfluorinated 1-methyl- ( 2) and 1-ethyl-benzocyclobutene ( 3) with bromine in an SbF 5 medium, cleavage of the four-membered ring of the starting compounds giving 2-bromoperfluoroisopropylbenzene ( 8) and 2-bromoperfluoro-sec-butylbenzene ( 9), respectively, was observed. In the system Br 2SbF 5, perfluorinated 1,1- ( 4) and 1,2-diethylbenzocyclobutene ( 5) undergo bromofluorination of the aromatic ring and breaking of the C 1C 2 bond of the four-membered ring. Thus, in the Br 2SbF 5 system, compound 5 gives 4-bromoperfluoro-1,2-dipropylcyclohexene ( 10) and perfluoro-1,2-dipropylcyclohexene ( 11), and isomer 4 gives perfluoro-1,1-diethyl-3,4,5,6-tetrahydrobenzocyclobutene ( 15) and perfluoro-1-methyl-2-(pent-2-ene-3-yl)cyclohexene ( 16). The latter is obtained by heating compound 15 with SbF 5 or CsF.