Redox‐Neutral Coupling between Two C(sp3)−H Bonds Enabled by 1,4‐Palladium Shift for the Synthesis of Fused Heterocycles

The intramolecular coupling of two C(sp3)−H bonds to forge a C(sp3)−C(sp3) bond is enabled by 1,4‐Pd shift from a trisubstituted aryl bromide. Contrary to most C(sp3)−C(sp3) cross‐dehydrogenative couplings, this reaction operates under redox‐neutral conditions, with the C−Br bond acting as an internal oxidant. Furthermore, it allows the coupling between two moderately acidic primary or secondary C−H bonds, which are adjacent to an oxygen or nitrogen atom on one side, and benzylic or adjacent to a carbonyl group on the other side. A variety of valuable fused heterocycles were obtained from easily accessible ortho‐bromophenol and aniline precursors. The second C−H bond cleavage was successfully replaced with carbonyl insertion to generate other types of C(sp3)‐C(sp3) bonds. A variety of fused heterocycles are obtained from easily accessible ortho‐bromophenol and aniline precursors by intramolecular coupling of two C(sp3)−H bonds, enabled by 1,4‐Pd shift from a trisubstituted aryl bromide. Unlike most C(sp3)−C(sp3) cross‐dehydrogenative couplings, this reaction operates under redox‐neutral conditions, with the C−Br bond acting as an internal oxidant.