Polyhalogenoallenes. Part III. Isomerisation of the dimer of tetrafluoroallene, perfluoro-(1,2-dimethylenecyclobutane), to perfluoro-(2-methyl-3-methylenecyclobutene)
Abstract
Pyrolysis, preferably in the presence of cæsium fluoride, of perfluoro-(1,2-dimethylenecyclobutane) effects its isomerisation to perfluoro-(2-methyl-3-methylenecyclobutene), the structure of which was confirmed by 19F nuclear magnetic resonance analysis of the compound itself and of its photo-dichlorides, 3-chloro-1-chlorodifluoromethyl-3,4,4-trifluoro-2-trifluoromethylcyclobutene and 3-chloro-3-chlorodifluoromethyl-1,4,4-trifluoro-2-trifluoromethylcyclobutene. Chemical shifts and coupling constants are tabulated.