Establishment of the mechanism a short history

Further evidence comes from the stmcture of statistical copolymers of cycloalkenes (Mj) with acetylenes (M2) in which the M1M2 junctions are present in sufficient proportion to be detectable by NMR. For example, a copolymer of cyclooctene and 2,4-dichlorophenylacetylene, containing 15% of Mi units, has been prepared using WCl4[OCH(CH2Cl)2]2/Et2AlCl as catalyst. The reactivity ratios are such that these units are nearly all flanked by M2 units and the olefinic 

A further confirmation of the metal carbene mechanism is provided by enyne intramolecular metathesis reactions such as that depicted in eqn. (22). The C=C bond in the substrate becomes the single bond attaching the alkenyl group to the phenanthrene ring (Katz 1985a, 1989) also see Section 10.4. 

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