Abstract Thermal and photochemical electrocyclic reactions of cis-perfluoro-1, 3, 5- hexatriene (I), 2, 3-dichlorotetrafluoro--1, 3-butadiene (II) and 1, 1, 2-trifluoro-1, 3-butadiene (III) were investigated. Thermal reaction of triene I in a vapour phase yielded perfluoro-1, 3- cyclohexadiene (IV) as a sole product whereas its photolysis in the vapour phase gave a mixture of perfluorobicyclo [2.2. 0] hex-2-ene (V) and perfluoro-3-vinylcyclobutene (VI). ...
