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

An enantioselective PdII/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. From CO to ketones with the introduction of α‐chirality: A PdII/Brønsted acid‐catalyzed enantioselective carbonylation–carbocyclization of enallenes has been developed, proceeding through an efficient CO and olefin insertion cascade to yield ketones with α‐chirality. A number of chiral cyclopentenones could be easily synthesized in good to excellent enantioselectivity and good yields.