Transanular polymerization

The intra-intermolecular propagations can result in ring structures of various sizes. For instance, three-membered rings can form from transanular polymerizations of bicycloheptadiene " ... 

Polynortricyclene [116-118] forms by cationic polymerization of norbomadiene by a transanular polymerization. 

NMR and IR spectra demonstrated that both propagations shown above take place during the polymerization and the resultant polymer is in effect a copolymer of both structures [119]. Similarly, cationic polymerization of 2-methylene, 5-norbomene involves a transanular addition of the initially formed carbon catimi to the strained endocycUc double bond. The product is a polymeric nortricyclane [119]. 

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