2,3,3-Trifluoro-1-cyclobutene and Dimers of 1,1,2-Trifluoro-1,3-butadiene from Tetrafluoroethylene-Vinylsilane Cycloadducts

Article abstract of DOI:10.1021/jo00199a013

(Tetrafluorocyclobutyl)silanes prepared by thermal cycloaddition of tetrafluoroethylene (TFE) to vinylsilanes were pyrolyzed at 600 deg C to give mixtures containing dimers of 1,1,2-trifluoro-1,3-butadiene.The monomeric diene 1 was undoubtly an intermediate formed by ring opening of initially formed 2,3,3-trifluoro-1-cyclobutene (9).This cyclobutene has been prepared by fluoride ion catalyzed removal of trimethylfluorosilane from (2,2,3,3-tetrafluorocyclobutyl)trimethylsilane (8) at room temperature.One of the dimers of the diene was saturated and was shown by X-raycrystallography to have the tricyclo<3.3.0.0>octane structure (3) corresponding to a previously reported structure for a perfluorobutadiene dimer.The cyclooctadiene 2 presumed to be the precursor to dimer 3 and Diels-Alder dimers (vinylcyclohexenes) 4 and 7 were characterized by 19F NMR analyses of liquid fractions.