Generation and trapping of a highly strained bicyclic allene: tricyclo[6.3.1.02,7]dodeca-2,4,6,9,10-pentaene

10-Bromo-10-fluorotetracyclo[6.3.1.02,7.09,11]dodeca-2,4,6-triene () was prepared by addition of bromofluorocarbene to benzonorbornadiene (). Treatment of a solution of in ether with MeLi in the presence of furan or styrene afforded the trapping products / and , respectively. The formation of these trapping products confirms the formation of the title cycloallene as a reactive intermediate.