Domino C–H functionalization reactions of gem-dibromoolefins: synthesis of N-fused benzo[c]carbazoles

A palladium-catalyzed domino transformation of gem-dibromoolefins leading to novel polycyclic benzo[c]carbazoles is described. A unique feature of the current reaction is the participation of both bromides in C–H functionalization processes. Mechanistic studies were conducted to ascertain the sequence of reaction events, and the results indicate that the (Z)-bromide likely reacts in preference to the (E)-bromide.