Lewis Acid‐Promoted C−H Chalcogenation of Arenes and Heteroarenes.

An efficient catalytic system employing TMS•OTf for the regioselective thiolation of electron‐rich arenes with sulfonyl hydrazides has been developed. The reaction occurs in a solvent mixture of dichloroethane and trifluoroethanol under mild conditions, with the addition of water. This method furnishes a range of para‐thio‐substituted arenes and 3‐sulfenyl‐indoles in good to excellent yields, marking a significant advancement in organic synthesis. [ABSTRACT FROM AUTHOR]