Synthesis and polymerization of fluorinated monomers bearing a reactive lateral group

The synthesis of various omega-perfluorovinyl synthons, especially 1,1,2-trifluoro-1,4-pentadiene I (F2C=CFCH2CH=CH2) is described. These products were prepared according to a three-step scheme via the photochemical addition of iodine monochloride to chlorotrifluotoethylene (CTFE) leading to ICF2CFCl2/ICFClCF2Cl isomers, the relative amount of which depending on the way of initiation. Their reaction with allyl acetate under radical conditions gave at least four isomers from the expected or rearranged compounds ClCF2CFClCH2CHXCH2Y or Cl2CFCF2CH2CHXCH2Y (with X, Y = I or OAc groups), the dechlorination and/or 'deiodoacetatisation' of which produced 1 and various 4,3,5,5,5-perhalogenopentanes as by-products. An optimization of the synthesis of 1 is proposed. All the compounds were characterized by H-1 and F-19 NMR. (C) 1998 Elsevier Science S.A. All rights reserved.