Photoexcited Palladium-Catalyzed Synthesis of Chiral Allenes from Alkynes via Isomerization and Deracemization Sequence

A photoexcited palladium-catalyzed synthesis of chiral allenes from alkynes via a sequence of isomerization and deracemization is disclosed. This method offers an efficient and cost-effective approach to produce a wide range of chiral allenes with good enantioselectivities and yields (up to 98% yield and 99% ee). The use of readily available and stable alkynes as starting materials simplifies experimental procedures and broadens the scope of the chiral allene synthesis. DBU plays a crucial dual role in this reaction to effectively facilitate the isomerization of alkynes to allenes and enhance the palladium-catalyzed deracemization under visible light excitation, both of which are vital for the success of the process.