Cyclopolymerization as a Route to Polyacetylenes

Although the polymerization of diene monomers is most familiar for 1,3-dienes, as in the production of rubbers, the polymerization of 1,6-dienes to yield polymers containing six-membered rings ( cyclopolymerization ) has been well established for many years43. Gibson et al.441 have used cyclopolymerization of 1,6-diynes to prepare polymers which are effectively substituted polyacetylenes, the archetype being the polymerization of 1,6-heptadiyne  

This reaction was described by Gibson et al. 441 and the properties of the polymer have been reviewed 45 . Ziegler polymerization gives the cyclopolymer as a soluble 

This isomerization is accompanied by a drop in conductivity. The polymer is also unstable in air, oxidising more rapidly than does Shirakawa polyacetylene. Both of these problems result from the allylic hydrogen atoms in the 3,5-positions of the monomer. In an effort to remove these hydrogens Gibson looked at at the polymer derived from propiolic anhydride  

---