Addition of free radicals to unsaturated systems. Part XX. The direction of radical addition of heptafluoro-2-iodopropane to vinyl fluoride, trifluoroethylene, and hexafluoropropene

Abstract

Heptafluoro-2-iodopropane reacts with vinyl fluoride under photochemical conditions to give a mixture of the 1:1 adducts 1,1,1,2,4-pentafluoro-4-iodo-2-trifluoromethylbutane and 1,1,1,2,3-pentafluoro-4-iodo-2-trifluoromethylbutane in high yield in the ratio 99:1; under thermal conditions the same adducts are formed in the ratio 97:3. Photochemical and thermal reaction with trifluoroethylene affords a mixture of the 1:1 adducts 1,1,1,2,3,4,4-heptafluoro-4-iodo-2-trifluoromethylbutane and 1,1,1,2,3,3,4-heptafluoro-4-iodo-2-trifluoromethylbutane in the ratios 96:4 and 85:15, respectively. In contrast, heptafluoro-2-iodopropane does not react smoothly with hexa-fluoropropene under comparable conditions.