Benzocyclobutene ring

The benzocyclobutene ring stmcture is a latent reactive diene because it tautomerizes to o-xylylene on heating according to the foUowiag ... 

TABLE 12. Poly cycles through benzocyclobutene ring opening... 

In general, the monomers that have been prepared and subsequently homopolymerized do not have a linking group between the double bond and the benzocyclobutene ring and R typically has been an aryl group. Table 18 lists the structures of those monomers which have been reported and Fig. 37 details the general process for their preparation. 

Stereoselective access to the basic skeleton of phyllocladane-type diterpencs is also possible via cocyclotrimerization of diynes. This is achieved upon conversion of a diyne containing a methylenecyclopentane unit in the side chain with l,2-bis(tiimethylsilyl)ethyne, and a subsequent cascade consisting of benzocyclobutene ring opening and an intramolecular Diels-Alder reaction44. 

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