The π elaborate then breaks right down to give the bromonium ion. A suitable therapy on the orbitals would hence not strictly be in the alkene and Br2, but of your orbitals in the π sophisticated alone. The predominance of allylic substitution over other positions relies on bond dissociation energies. https://jaideneazul.pointblog.net/solution-de-bromoforme-an-overview-84867393