One-pot synthesis of aryl- as well as heteroaryl-annulated carbazoles was achieved from 2/3-bromomethylindoles involving Lewis acid mediated domino reaction with arenes as well as heteroarenes via successive Friedel–Crafts intermolecular as well as intramolecular alkylations followed by elimination of acetone. Further, the bis-domino reaction of 2,5-bis(bromomethyl)pyrrole was also carried out with selected heteroarenes. Additionally, the synthesized thienocarbazoles and thienodibenzofurans were successfully utilized for a second-generation domino reaction.
Key words
carbazole - indole - pyrrole - Friedel–Crafts alkylation - Michael addition