Enantioselective Palladium‐Catalyzed Carbonylative Carbocyclization of Enallenes via Cross‐Dehydrogenative Coupling with Terminal Alkynes: Efficient Construction of α‐Chirality of Ketones

An enantioselective Pd^II/Brønsted acid‐catalyzed carbonylative carbocyclization of enallenes ending with a cross‐dehydrogenative coupling (CDC) with a terminal alkyne was developed. VAPOL phosphoric acid was found as the best co‐catalyst among the examined 28 chiral acids, for inducing the enantioselectivity of α‐chiral ketones. As a result, a number of chiral cyclopentenones were easily synthesized in good to excellent enantiomeric ratio with good yields.