Rearrangement of Bicyclo(2.2.2)octa-2,5-diene and Bicyclo(3.2.2)nona-6,8-diene under the Conditions of Bromination.

A reaction of electrophilic bromination of norbornadiene homologs such as bicyclo[2.2.2]octa-2,5-diene (4) and bicyclo[3.2.2]nona-6,8-diene (7) with bromine gave hitherto unknown skeleton rearranged dibromides. The rearrangement may proceed via a bromonium cation of starring diene to give bicyclo[3.2.1]octene or bicyclo[3.3.1]nonene skeleton in respective cases. The observed rearrangement reactions are also confirmed in 6,7-bis(methoxycarbonyl) derivatives of bicyclodiene 7 under similar conditions.