Thermalisomerization of [1.1.1]propellane in a flow system at 370°C led to a 3:2 mixture of bicyclo[5.1.0]octa-1,6-diene () and 6-vinylidenebicyclo[3.1.0]hexane (). At 430°C, propellanes and were converted into 1,2-divinylcyclopropene (), and, respectively, into dimethylenecyclopropane ().