Some reactions of 1,2,3,4,7,7-hexafluorobicyclo[2,2,1]hepta-2,5-diene: Thermolysis and attack by methoxide ion and by bistrifluoromethyl nitroxide

Abstract

1,2,3,4,7,7-Hexafluorobicyclo[2,2,1]hepta-2,5-diene gave 1,2,3,4-tetrafluorebenzene in at least 73% yield when heated to 450°C in a sealed tube; the CF 2 bridge appeared, in part, as octafluorocyclobutane. Nucleophilic attack by sodium methoxide- methanol on the diene occurred exclusively at the CFCF bond, causing the formation of 1,2,4,7,7-pentafluoro-3-methoxybicyclo- [2,2,1]hepta-2,5-diene and a 1,4,5,6,7,7-hexafluoro-5-methoxybicyclo [2,2,1]hept-2-ene thought, on the basis of 19F nmr data, to be the 6- endo -F,5- exo -MeO isomer. Radical attack on 1,2,3,- 4,7,7-hexafluorobicyclo[2,2,1]hepta-2,5-diene by bistrifluoromethyl nitroxide took place at both olefinic sites, with a ca . 10:1 preference for the CFCF linkage; all three geometrical isomers of 5,6-bis(bistrifluoromethylamino-oxy)-1,4,5,6,7,7- hexafluorobicyclo[2,2,1]hept-2-ene were formed.