The bromination of 6,7,8,9-tetrahydro-5H-5,9-ethenobenzo[a][7]annulene yielded regio- and stereospecifically formed dibromides arising from the alkyl shift where the bromine exclusively attacks the doublebond from the endo face of the double bond. DFT calculations on model compounds showed that thepyramidalization of the double bond and steric repulsion caused by the methylene protons are responsiblefor the stereo- and regioselective addition of bromine.