Synthesis of benzo[b]thieno‐ and benzo[b]furano‐[2,3‐a]pyrrolo[3,4‐c]carbazole‐5‐, ‐7‐ and ‐5,7‐dione

Benzob]thieno2,3‐a]pyrrolo3,4‐c]carbazoles and benzob]furano2,3‐a]pyrrolo3,4‐c]carbazoles were prepared from 2‐(2‐benzob]thieno)‐ (8) and 2‐(2‐benzob]furano)‐3‐3‐(2,5‐dioxo‐lH‐pyrrolidinyl)]indole (9) by a palladium(II)acetate/tetrachloro‐1,4‐benzoquinone oxidative A‐E ring closure.