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

A series of epoxybenzo[ k ]fluoranthenes, epoxy-5 H -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(sp 2 or sp 3 )-H activation being a key step. The enantioselective version of the reaction was also briefly explored.