Synthesis of 6- and 7-Arylindoles<i>via</i>Palladium-Catalyzed Cross-Coupling of 6- and 7-Bromoindole with Arylboronic Acids

Abstract

Couplings of 6- and 7-bromoindole with various arylboronic acids were effected via the Suzuki reaction. This method provided good yields and was found to be suitable for scale-up to 10-20 grams of the desired arylindole products. The primary advantage of this cross-coupling method is that indole functionalization or nitrogen protection is unnecessary. Also, during these investigations a known synthesis of 6-bromoindole was improved, and the revised procedure is amenable to large-scale preparation.