The first and efficient synthesis of some of the polyhalogenated benzobarrelenes: unusual formation of a benzosemibullvalene derivative

New polyhalogenated benzobarrelenes were synthesized in good yields. The bromination reaction of benzobarrelenes at high temperature gives non-rearranged products. Dehydrobromination of the formed products with t-BuOK yielded the desired polyhalogenated benzobarrelenes. The elimination reaction of cyclopropanoid dibromide with a base unusually resulted in the formation of a benzosemibullvalene derivative. (C) 2009 Elsevier Ltd. All rights reserved.