Pd-Catalyzed Cascade Reaction for the Synthesis of 2-Substituted Indoles

An efficient cascade methodology toward the synthesis of 2-substituted indoles has been developed. The transformation proceeds via a palladium-catalyzed cross-coupling reaction of o-nitrobenzyl cyanides with boronic acids. The use of Fe as co-catalyst during the course of reaction employs significant enhancement in reaction rates. The developed protocol allows for the unprecedented use of arylboronic acids as coupling partners for constructing 2-substituted indoles.