Diels-alder reaction between butadiene and cyclopentadiene

Abstract

Diels-Alder reaction of cyclopentadiene with 4-vinyl-cyclohexene (1), 5-vinyl-2-norbornene (2), 3a, 4, 7, 7 α-tetrahydroindene (3) or dicyclopentadiene (4) prepared by the dimerization reaction between butadiene and cyclopentadiene, was investigated. In the reaction at high temperatures, the isomerization of vinylnorbornene to tetrahydroindene first took place, and the trimers obtained from the reaction of vinylnorbornene were similar to those obtained from tetrahydroindene. Meanwhile, owing to the isomerization of endo-dicyclopentadiene to exo-form, the cyclopentadiene trimer was derived from the latter isomer. The relative reactivity of the double bonds on dimers shown in the following figure was affected by the whole structure of dimer, and the values obtained for double bonds of the same type varied depending upon each compound. © 1972, The Japan Petroleum Institute. All rights reserved.