BROMINATION OF EXO-TRICYCLO[3.2.1.0(2,4)]OCT-6-ENE AND ENDO-TRICYCLO[3.2.1.0(2,4)]OCT-6-ENE

Bromination of exo- and endo-tricyclo[3.2.1.0(2,4)]oct-6-ene is initia ted at the double bond. This is in contrast to reaction with acid wher e reaction is initiated preferentially at the cyclopropane. The statio nary points on the potential energy surfaces that result from bromine addition to the double bond have been identified by semi-empirical met hods. The non-classical bromonium ions are predicted to be less stable than the classical structures. The exo-cyclopropylalkene gives cis an d trans 1,2-dibromides along with products which result from reaction of bromine at the exo face of the alkene with subsequent rearrangement involving the C2C4 or C2C3 cyclopropyl bonds. The endo-cyclopropylalk ene similarly reacts with bromine at the exo face of the alkene, but 1 ,2-addition does not compete with rearrangement.