Divergent Construction of Spirocyclopentene-3,2′-indolines with Vicinal Stereocenters via Palladium-Catalyzed Aza-Wacker Cyclization

Herein, we report an aerobic palladium-catalyzed aza-Wacker cyclization to produce spirocyclopentene-3,2'-indolines with vicinal stereocenters. Using 1,2-bis(diphenylphosphino)benzene (dppbz) and pyridine as ligands, we achieved a ligand-modulated diastereodivergent synthesis, producing <i>cis</i>- and <i>trans</i>-spirocyclopentene-3,2'-indolines with exceptional yields and diastereoselectivities. Density functional theory (DFT) calculations revealed that selective aza-Wacker cyclization proceeds through distinct <i>trans</i>- and <i>cis</i>-aminopalladation mechanisms.