Palladium-Catalyzed C–S Bond Formation of Stable Enamines with Arene/Alkanethiols: Highly Regioselective Synthesis of β-Amino Sulfides

A direct and regiocontrolled thiolation method to access β-amino sulfides through the palladium-catalyzed C(sp²)–H functionalization of stable enamines was described. The reaction was realized under mild conditions by adding an external phosphine ligand to prevent poisoning of the palladium catalyst by the sulfuric reagents. A possible mechanism was proposed according to the obtained results. The DFT calculation results were consistent with the experiment data, which gave the E isomers of the β-amino sulfides. The reaction was also performed on a gram scale and shows potential application in organic synthesis.