Direct cross-coupling access to diverse aromatic sulfide: Palladium-catalyzed double C-S bond construction using Na₂S ₂O₃ as a sulfurating reagent

The Pd-catalyzed cross-coupling of aryl halides, alkyl halides, and Na ₂S₂O₃·5H₂O to deliver aromatic thioethers is described. Pyridine, furan, thiophene, benzofuran, benzoxazole, benzothiophene, benzothiazole, and pyrazine are all amenable to this protocol. The odorless and stable solid Na₂S₂O ₃·5H₂O was used as a convenient and environmentally friendly source of sulfur. Pd-catalyzed cross-couplings without thiols or thiophenols to build C-S bonds have not previously been achieved, which renders our observation more striking.