The bromination of bicyclo[3.2.1]octa-2,6-diene with N-bromosuccinimide

The bromination of bicyclo3.2.1]octa-2,6-diene (3) by NBS does not follow the familiar free-radical course but proceeds through the cyclopropylcarbinyl cation 7. 7 can be trapped by addition of small amounts of methanol. The bicyclo3.2.1]octa-2,6-dien-4-yl radical is involved in the reduction of exo-6-bromotricyclo 3.2.1.0^2,7]oct-3-ene by tributyltin hydride.