Benzvalene, ring-opening metathesis polymerization

A drawback to the Durham method for the synthesis of polyacetylene is the necessity of elimination of a relatively large molecule during conversion. This can be overcome by the inclusion of strained rings into the precursor polymer stmcture. This technique was developed in the investigation of the ring-opening metathesis polymerization (ROMP) of benzvalene as shown in equation 3 (31). 

Benzvalene, a valence isomer of benzene, has been polymerized by ring-opening metathesis polymerization in the presence of tungsten-carbene complexes to form polybenzvalene [Eq. 83)]. 

---