SYNTHESIS OF TELECHELIC DIENES FROM FLUORINATED ALPHA,OMEGA-DIIODOALKANES .1. DIVINYL AND DIALLYL DERIVATIVES FROM MODEL I(C2F4)NI COMPOUNDS

The synthesis of five fluorinated non-conjugated dienes from commercially available alpha,omega-diiodoperfluoroalkanes is described. Preparation of the fluorinated divinyl derivatives H2C=CH(CF2)(n)CH=CH2 (n=2, 4, 6) (2,2, 2,4 and 2,6) was effected by ethylenation of these diiodinated compounds in various ways followed by dehydroiodination in ethanolic potassium hydroxide. Allyl diolefines, H2C=CHCH2(CF2)(n)CH2CH=CH2 (4,4 and 4,6) were produced by the alpha,omega-bis-telomerization of allyl acetate followed by deiodoacetoxylation in the presence of zinc. The diacetate precursors 3,4 and 3,6 of the respective diallyls 4,4 and 4,6 were obtained rather than diacetate 3,2 because of the eventual decomposition of alpha,omega-diiodoperfluoroethane by beta-scission. These five fluorinated non-conjugated dienes have been characterized by H-1, C-13 and F-19 NMR spectroscopy.