Palladium‐Catalyzed C3‐Carbaldehyde Directed Regioselective C2‐Thioarylation of Indoles

Abstract Palladium‐catalyzed thioarylation of indoles by diaryl disulfides in the presence of phenyliododiacetate is reported. The directing potential of weakly coordinating aldehyde group present at 3‐position of indole was exploited for regioselective C2‐H thioarylation over the possible C4‐H functionalization. Mechanistic studies reveal that the process involves initial generation of thioaryl radical followed by sequential C−H activation, thiolate transfer, and reductive elimination.