Site‐Selective C−S Bond Formation at C−Br over C−OTf and C−Cl Enabled by an Air‐Stable, Easily Recoverable, and Recyclable Palladium(I) Catalyst

This report widens the repertoire of emerging Pd(I) catalysis to carbon–heteroatom, that is, C−S bond formation. While Pd(0)‐catalyzed protocols may suffer from the formation of poisonous sulfide‐bound off‐cycle intermediates and lack of selectivity, the mechanistically diverse Pd(I) catalysis concept circumvents these challenges and allows for C−S bond formation (S–aryl and S–alkyl) of a wide range of aryl halides. Site‐selective thiolations of C−Br sites in the presence of C−Cl and C−OTf were achieved in a general and a priori predictable fashion. Computational, spectroscopic, X‐ray, and reactivity data support dinuclear Pd(I) catalysis to be operative. Contrary to air‐sensitive Pd(0), the active Pd(I) species was easily recovered in the open atmosphere and subjected to multiple rounds of recycling.