Palladium-Catalyzed [3 + 2] Annulation of Aryl Halides with 7-Oxa- and 7-Azabenzonorbornadienes via C(sp2 or sp3)-H Activation.

A series of epoxybenzo[k]fluoranthenes, epoxy-5H-benzo[b]fluorenes, and their aza analogues have been accessed via palladium-catalyzed exo-selective [3 + 2] annulation between aryl halides and 7-oxa- and 7-azabenzonorbornadienes. The reaction is initiated by the oxidative addition of a carbon-halogen bond, with intramolecular C(sp2 or sp3)-H activation being a key step. The enantioselective version of the reaction was also briefly explored.