The addition of bromine to dibenzobicyclo/2.2.2/octatriene (1) leads t
o exo-4-syn-8-dibromide 6, as product of kinetic control. Compound 6,
under the action of molecular bromine (which acts as ionizing reagent)
afforded the thermodynamic control product, endo-4-syn-8-dibromide 4.