Transalkylation or Transalkylidenation

The first question which arises about the mechanism of metathesis reac- 

Early work using and deuterium labelled propene and butene quickly established that two olefinic bonds are switched between four carbon atoms, the integrity of all other bonds within the alkenes remain intact [18]. 

A similar mechanism has been postulated for reactions involving cycloalkenes. It has been shown that a copolymer of cyclooctene and cyclopentene (labelled on its double bond with is predominantly labelled in the C5 fragment, this result being obtained by reductive ozonolysis of the polymer [9j. The radioactivity found in the C5 diol proves that ring opening polymerization also proceeds via scission on the double bonds rather than cleavage of carbon—carbon single bonds. 

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