Regiospecific 2,3‐Dialkylindole Synthesis Enabled by Alkylpalladium 1,2‐Migration to In Situ Formed Aldimine

Abstract

Abstract2,3‐Dialkylindoles play crucial roles in natural products and pharmaceuticals, but the step‐efficient and regioselective construction of such privileged structures remains a long‐standing challenge. Here, we report a regiospecific non‐Fischer indole synthesis through chemoselective 1,2‐migratory addition of alkylpalladium to an aldimine intermediate, formed in situ through a palladium hydride‐triggered sequential isocyanide and intramolecular olefin insertion. This unprecedented 1,2‐migratory addition leads to formal C═C bond cleavage and isocyano carbon insertion between the two sp2 carbons, offering a novel approach to specific 2,3‐dialkyl substituted N─H free indoles from readily available alkyl substituted 1‐isocyano‐2‐vinylbenzenes.