Palladium-Catalyzed Enantioselective Cyclization of 1,6-Enynes to Access Chiral γ‑Butyrolactam

A palladium-catalyzed asymmetric chlorocyclization of\n1,6-enynes\nhas been described. Controlling the chloride ion concentration in\nthe system by substrate design is the key to achieving asymmetric\nchlorinated cyclization. In the presence of Pd(PhCN)<sub>2</sub>Cl<sub>2</sub> and chiral phosphoramidite ligands, the reaction accesses\ndiverse chiral (<i>E</i>)-α-chloromethylene-γ-butyrolactams\nwith excellent <i>E</i> selectivity and enantioselectivity.\nThe strategy features simple operations and mild conditions, offering\na practical and reliable route for the synthesis of chiral butyrolactam\ncompounds.