Cyclooctatetraenes ring-opening polymerization

Optically active polyacetylene derivatives 97 were synthesized through ring-opening polymerization of the corresponding cyclooctatetraene derivatives.25 A twisted conformation of the main chain was proposed on the basis of CD and UV absorptions. Various optically active polyacetylenes have also been prepared from chiral monomers.24,25,263,177-183 The examples include a phenylacetylene derivative (98),26a alkylacetylenes 99,24 propionic esters such as 100,177,178 a Si-containing monomer (101),179 and disubstituted monomers such as 102.180 Poly-(A)-98 synthesized using a [RhCl(norbornadiene)]2 catalyst shows intense CD bands in the UV—vis region, probably based on a predominant helical sense of the main chain.263 This polymer effectively resolves several racemic... 

Much yet remains to be done as regards the choice of the pendent radicals. The ring-opening metathesis polymerization of cyclooctatetraenes (Gins-burg et ai, 1989 Klavetter and Grubbs, 1988) has not yet been applied to the construction of high-spin polyacetylenes. 

Langsdorf BL, Zhou X, Lonergan MC. Kinetic study of the ring-opening metathesis polymerization of ionically functionalized cyclooctatetraenes. Macromolecules 2001 34 2450-2458. 

Substituted polyacetylenes may be produced through the ring-opening metathesis polymerization of substituted cyclooctatetraenes.127... 

Partially substituted derivatives of polyacetylene are synthesized via the ring-opening metathesis polymerization (ROMP) of cyclooctatetraene (COT) and its derivatives. Certain poly-COT derivatives afford soluble, highly conjugated poly acetylenes. These materials exhibit large third-order optical nonlinearities and low scattering losses. 

Gorman, C.B., Ginsburg, E.J., Grubbs, R.H., 1993. Soluble, highly conjugated derivatives of polyacetylene from the ring-opening metathesis polymerization of monosubstituted cyclooctatetraenes synthesis and the relationship between polymer structure and physical properties. I. Am. Chem. Soc. 115, 1397-1409. 

Jozefiak, T. H., Ginsburg, E. J., Gorman, C. B., Grubbs, R. H., and Lewis, N. S., Voltammetric characterization of soluble polyacetylene derivatives obtained from the ring opening metathesis polymerization (romp) of substituted cyclooctatetraenes, J. Am. Chem. Soc., 115, 4705-4713 (1993). 

Various routes to polyacetylene and derivatives. A. Direct Ziegler-Natta polymerization of acetylene as developed by Shirakawa. B. Feast s retro Diels-Alder, precursor polymer route. C. Ring-opening metathesis pol)rmerization (ROMP) of a substituted cyclooctatetraene as developed by Grubbs. 

Fig. 7.7 Well-defined catalysts for the ring-opening metathesis polymerization of 1,3,5,7-cyclooctatetraene.

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