Synthesis of telechelic dienes from fluorinated alpha,omega-diiodo alkanes .2. Divinyls and diallyls containing tetrafluoroethylene, vinylidene fluoride and hexafluoropropene

Synthesis of new fluorinated non-conjugated dienes containing tetrafluoroethylene, vinylidene fluoride (VDF) and/or hexafluoropropene from alpha,omega-diiodofluorinated cotelomers was carried out by two methods in two steps. Divinyl monomers were obtained by alpha,omega-bis ethylenation of these cotelomers followed by a bis-dehydroiodination in medium yields which were lower when the cotelomers contained the VDF base unit. Diallylic olefins were produced by addition of these alpha,omega-diiodofluoroalkanes to allyl acetate followed by a 'deiodoacetatization' in high yields. Each telechelic diene was carefully characterized by H-1 and F-19 NMR.