Chelation-assisted and steric-controlled selectivity in the Pd-catalyzed C–H/C–H oxidative coupling of indoles

Abstract

We report the first regioselective C2–C7 oxidative coupling of indoles using a palladium catalyst upon the strategic installation of N-pyridinyl and C3-carbonyl, which delivers 2,7-biindoles with a broad scope (25 examples; up to 93% yield). Isolation of the catalytic intermediate reveals the initial activation of the C(7)–H bond, followed by the C(2)–H bond in indoles, and the reaction proceeds via a Pd(II)/Pd(0) pathway.