文摘
A novel palladium-catalyzed annulation reaction of in situ generated arynes and o-halostyrenes has been developed. This methodology affords moderate to excellent yields of substituted phenanthrenes and is tolerant of a variety of functional groups such as nitrile, ester, amide, and ketone. This annulation chemistry has been successfully applied to the formal total synthesis of a biologically active alkaloid (±)-tylophorine.