A simple route to 3-(dihalomethylene)cyclo-alkenes

Thermolysis of a number of bicyclic trihalocyclopropanes (1; X, Y = halogen) in the presence of quinoline leads either to 3-(dihalomethylene)cyclo-alkenes (8,9,10) with loss of halogen X $\text{or}$ to ring expanded 1,2-dihalocycloalka-1,3-dienes (11,13) with loss of halogen Y, depending on ring size and on the nature of the halogen.