1,2,3,3,6,6-hexafluoro-4-phenylcyclohexa-1,4-diene

(3,3,4-trifluoro-4-(1,2,2-trifluorovinyl)cyclobut-1-en-1-yl)benzene

1-phenyl-4-tetrafluoroethylidene-3,3-difluoro-1-cyclobutene

3,4-dichlorohexafluoro-1-butene

(E)-1,4-dichloro-1,1,2,3,4,4-hexafluorobut-2-ene