Thermolytic reactions of polyfluoroorganic compounds. Part XXVII. Interaction of 1,1- dichloropolyfluoroindanes with haloforms

The high-temperature alicyclic ring contraction of 1,1-dichloroperfluorotetralin and the alicyclic ring opening of 1,1-dichloroperfluorobenzocyclobutene

“…This explanation is in accordance with the fact that mixtures of compounds 1, 6 and 1, 2, 6, 7, similar to that for tetralin 4, are formed in the copyrolysis of compound 3 with CHClF 2 [3] and in its high-temperature reaction in a stream of argon, respectively (Scheme 2).…”

“…The reaction mixture also contains small amount of perfluoro-3-methylindene (6), which is a product of isomerization of compound 1 under the reaction conditions [3], together with unidentified impurities (Scheme 2). The formation of compounds 1 and 6 takes place also in the pyrolysis of tetralin 4 in a stream of argon.…”

“…But this route is improbable because compound 3, which is formed in the reaction of indan 2 with CHClF 2 at 570 8C [3], was not identified in the reaction mixture obtained in copyrolysis of compound 5 with CHClF 2 at this temperature.…”

“…Copyrolysis of a,a-dichloropolyfluoroalkylbenzenes [1,2] and 1,1-dichloropolyfluoroindans [3] with CHClF 2 as a source of difluorocarbene [4,5] is known to give polyfluorostyrenes and polyfluoro-1-methyleneindans, respectively. It has been shown that formation of perfluoro-1-methyleneindan (1) in the reaction of 1,1-dichloroperfluoroindan (2) with CHClF 2 can proceed by way of difluorocarbene insertion into C-Cl bond of compound 2, giving 1-chloro-1-(chlorodifluoromethyl)perfluoroindan (3), with subsequent dechlorination of the latter [3] (Scheme 1).…”

“…It has been shown that formation of perfluoro-1-methyleneindan (1) in the reaction of 1,1-dichloroperfluoroindan (2) with CHClF 2 can proceed by way of difluorocarbene insertion into C-Cl bond of compound 2, giving 1-chloro-1-(chlorodifluoromethyl)perfluoroindan (3), with subsequent dechlorination of the latter [3] (Scheme 1).…”