The high-temperature bromination of 1a,2,7,7a-tetrahydro-1H-cyclopropa[b] naphthalene and its carboethoxy derivative was studied. Reaction of the title compound with 1 mol of bromine in refluxing carbon tetrachloride resulted in the formation of ring-opening products. In the case of the carboethoxy derivative,bromination took place both regio- and stereospecifically at the benzylic positions,the cyclopropane ring did not undergo bond cleavage. A mechanism for the formation of the products and their dehydrobromination reactions is discussed. (c) 2007 Elsevier Ltd. All rights reserved.