Synthesis of functionalized indole- and benzo-fused heterocyclic derivatives through anionic benzyne cyclization

Chemistry. 2002 May 3;8(9):2034-46. doi: 10.1002/1521-3765(20020503)8:9<2034::AID-CHEM2034>3.0.CO;2-I.

Abstract

The development of a new method for the regioselective synthesis of functionalized indoles and six-membered benzo-fused N-, O-, and S-heterocycles is reported. The key step involves the generation of a benzyne-tethered vinyl or aryllithium compound that undergoes a subsequent intramolecular anionic cyclization. Reaction of the organolithium intermediates with selected electrophiles allows the preparation of a wide variety of indole, tetrahydrocarbazole, dihydrofenantridine, dibenzopyran, and dibenzothiopyran derivatives. Finally, the application of this strategy to the appropriate starting materials allows the preparation of some tryptamine and serotonin analogues.