Unlocking thePhosphoric Acid Catalyzed AsymmetricTransfer Hydrogenation of 2‑Alkenyl Quinolines for EfficientFlow Synthesis of Hancock Alkaloids

Chiral tetrahydroquinolines are present in several bioactive molecules, such as the Hancock alkaloids. Although the organocatalytic asymmetric transfer hydrogenation of 2-aryl quinolines has emerged as a safer alternative to using hydrogen gas, analogous reactions with 2-alkenyl quinolines remain unexplored. Here we present a protocol to synthesize key enantioenriched intermediates to the Hancock alkaloids, providing a constant outcome for, at least, a 24 h continuous flow operation.