Aryl trifluorovinyl ether monomers

In this chapter, various synthesis routes for trifluorovinyl aromatic ethers are discussed. PFCB polymers are prepared via thermally activated [2+2] cycloaddition of aryl trifluorovinyl ether monomers. The cyclodimerizaton proceeds in a stereorandom fashion giving a roughly equal distribution of cis- and trans- stereoisomers. The PFCB technology can serve as a versatile materials platform for many industrial... 

Babb, D. A. Snelgrove, R. V. Smith, D. W., Jr. Mudrich, S. F. Novel Step-Growth Polymers from the Thermal (2p - -2pj Cyclopolymerization of Aryl Trifluorovinyl Ether Monomers-, ACS Symposium Series ACS Publications, 1996 pp 431 41. 

The substituent sensitivity of this reaction is such that the trifluorostyrenes (proceeding through a benzylic diradical) have been shown to dimerize veiy efficiently at room temperature (72). Insertion of the oxygen atom to form an aryl trifluorovinyl ether pushes the kinetically-significant dimerization temperature to over 100°C and provides monomers with sufficient shelf stability for most applications. Figure 4 illustrates a typical neat polymerization by differential scanning calorimetry (DSC) where the onset of exothermic polymerization is detected near 140 °C as is observed similarly for most monomers studied in our labs. 

S. Wong, H. Ma, A.K.Y. Jen, R. Barto, C.W. Frank, Highly fluorinated trifluorovinyl aryl ether monomers and perfluorocyclobu-tane aromatic ether polymers for optical waveguide applications. Macromolecules 36 (21) (2003)8001-8007. 

The current intensified interests in the preparation of PEMs have prompted us to synthesize aromatic monomers such as trifluorovinyl ethers functionalized by acid groups. In particular, we reported the first preparation of 4-[(a,, -trifluorovinyl)oxy] benzene phosphonic acid (Fig. 2.21) [99]. [(a,, -Trifluorovinyl)oxy]benzene dialkyl phosphonate was prepared by several phosphonation methods, such as Michaehs-Arbuzov, Michaelis-Becker, or palladium-catalyzed arylation in the presence of various reactants. The reaction involving palladium triphenylphosphine as the catalyst led to the best yield [99]. 

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