Addition Oligomerization of Dicyclopentadiene: Reactivity of Endo and Exo Isomers and Postmodification

The oligomerization of dicyclopentadiene (DCPD, mixture of endo and exo isomers), 9,10-dihydrodicyclopentadiene (H-DCPD), exo-DCPD, and endo-DCPD catalyzed by TiCl4/Et2AlCl is studied. Oligomers containing 2,3-enchained units are obtained in good yields. The endo-DCPD is less reactive than the exo isomer, exhibiting a reactivity comparable with that of the partially saturated H-DCPD. While all the products obtained from the oligomerization of the exo isomer and H-DCPD are amorphous, from the endo isomer, at low DCPD/Ti ratio, a crystalline, stereoregular tetramer having a 2,3-exo-disyndiotactic structure is obtained. The results show that the presence of the double bond in the cyclopentene ring, the spatial disposition of the cyclopentene, and the oligomerization conditions play a fundamental role to give a unique crystalline material. Hydrogenation and epoxidation of the obtained products are reported as well.