Bromination of norbornene derivatives: synthesis of brominated norbornanes and norbornenes

The low and high temperature bromination of 7-bromobicyclo[2.2.1]hept-2-ene and 2,7-dibromobicyclo[2.2.1]hept-2-ene were studied and the possible role of a neighboring group participation in rearrangements was investigated. The formation mechanism of the isomers as well as the role of the substituent on the rearrangement were discussed. The structure elucidation of the formed compounds was achieved by NMR spectral data; particularly, the γ-gauche effect was discussed in connection with the configuration of the bromine atoms.