Thermal Transformations of 2,5-Difluoro-3,4,6-trichlorobenzenethiol with Tetrafluoroethylene

Pyrolysis of a mixture of 2,5-difluoro-3,4,6-trichlorobenzenethiol with tetrafluoroethylene leads to 2,2,3,3,4,7-hexafluoro-5,6-dichloro-2,3-dihydrobenzo[b]thiophene (the major reaction product) along with 2,2,3,3,4,6-hexafluoro-5,7-dichloro-2,3-dihydrobenzo[b]thiophene. Schemes of their formation with the participation of intermediate radicals are proposed. Oxidation of a mixture of the synthesized compounds gave 2,2,3,3,4,7-hexafluoro-5,6-dichloro-2,3-dihydrobenzo[b]sulfane-1,1-dioxide and 2,2,3,3,4,6-hexafluoro-5,7-dichloro-2,3-dihydrobenzo[b]sulfane-1,1-dioxide.