Studies in the cycloproparene series: 2-halocyclopropabenzenes

Labelling studies show that dehydrohalogenation of the tetrahalobicycloheptane (8b,c) yields the title compounds (5a,b) both with and without skeletal rearrangement. 2-Chlorocyclopropabenzene (5b) is the major product and the expected 2-bromo derivative (5a) the minor product of reaction from the ‘mixed’ tetrahalide (8c).