Synthesis of 2,3-disubstituted indoles by palladium-mediated coupling of 2-iodoindoles

Abstract

N-Unprotected 2-iodoindoles are synthesized by treatment of 2- stannylindoles with iodine, which in turn are prepared by tin-mediated radical cyclization of 2-alkenylphenylisocyanides. Palladium-catalyzed coupling reactions of N-unprotected 2-iodoindoles with terminal acetylenes, terminal olefins, carbonylation, and the Suzuki coupling reaction with phenyl borate proceed smoothly to furnish the corresponding 2,3-disubstituted indoles in good to excellent yields.