Chiral Phosphoric Acid‐Catalyzed Dynamic Kinetic Asymmetric Reductive Amination: Accessing 8‐Arylquinoline Atropisomers

Disclosed here is an atroposelective dynamic kinetic asymmetric reductive amination catalyzed by chiral phosphoric acid, which provides access to a series of axially chiral 8‐arylquinolines in 50–97% yields with good‐to‐high enantioselectivities (85.5:14.5‐96:4 er). The formation of quinolinium cation intermediate is found to play a key role in facilitating racemization, thereby enabling a dynamic kinetic resolution scenario. The broad functional group tolerance and versatile downstream functionalization demonstrate utility of current methodology. Interestingly, significant enantiomeric enrichment of 8‐arylquinoline products is achieved by “one‐pot” two‐step asymmetric transfer hydrogenation thanks to a “matched” cascade kinetic resolution step (up to > 99:1 er)