Pd-Catalyzed Synthesis of Carbazoles and α-Carbolines via C-H Activation

Significance

Reported is a Pd-catalyzed synthesis of annulated tricyclic heterocycles from readily available anilines and 1,2-dihaloarenes and -heteroarenes. This sequential C-C and C-N bond-forming process involves an amination and a direct C-H bond activation-cyclization and proceeds on anilines and diarylamines to give carbazoles and α-carbolines with high regioselectivity and in good yields. A single case of coupling of diphenylamine with 1,2-dibromocyclopentene also proceeded well to give a fused indole derivative.