Bimolecular Reactions of 3-Methylene-1,4-cyclohexadiene (p-Isotoluene), 5-Methylene-1,3-cyclohexadiene (o-Isotoluene), 1-Methylene-1,4-dihydronaphthalene (Benzo-p-isotoluene), and 9-Methylene-9,10-dihydroanthracene (Dibenzo-p-isotoluene)

Article abstract of DOI:10.1021/jo00263a021

3-Methylene-1,4-cyclohexadiene, 1, 5-methylene-1,3-cyclohexadiene, 2, 1-methylene-1,4-dihydronaphthalene, 5, and 9-methylene-9,10-dihydroanthracene, 8, react with second-order kinetics in benzene solution.The activation parameters for the reaction of 1,5,and 8, especially the frequency factor, suggest a nonconcerted reaction with little orientational demand in the transition state.The frequency factor for the reaction of 2 suggests a concerted pathway.The product distribution from each compound reinforces the kinetic observations.The products from the pyrolysisof 1 could be rationalized by a radical cage intermediate, which could combine or disproportionate.The reaction products from 5 indicate a radical chain oligomerization.The reaction of 8 gives an insoluble solid. o-Isotoluene (2) gives ene dimers.