Atroposelective Brønsted Acid-Catalyzed Photocyclization to Access Chiral N -Aryl Quinolones with Low Rotational Barriers.

Herein, a novel route to atropisomeric N -aryl quinolones with low rotational barriers is demonstrated, leveraging a dual photochemical/organocatalytic approach to the required ring closure in up to 94% yield and up to >99% ee. The use of a continuous flow system allows for impurity suppression and enables rapid scale-up to a decagram scale.