Die Addition von Fluorcarbenen an Norbornadien: Eine Homo-1,4-addition

It has been found that difluorocarbene undergoes extensive addition to the endo-face of norbornadiene, yeilding the cheletropic adduct, 4.4-difluorotetracyclo[3.3.0.0^2,8.0^3,6]-octane. Similar behaviour has been observed for fluorochlorocarbene. Possible mechanisms to rationalize this novel behaviour of carbenes are discussed.