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

Abstract The intramolecular coupling of two C(sp 3 )−H bonds to forge a C(sp 3 )−C(sp 3 ) bond is enabled by 1,4‐Pd shift from a trisubstituted aryl bromide. Contrary to most C(sp 3 )−C(sp 3 ) 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(sp 3 )‐C(sp 3 ) bonds.