Dynamic kinetic resolution and dynamic kinetic asymmetric transformation of atropisomeric biaryls

Atropisomeric biaryl compounds bearing axial chirality have been gaining increasing attention in organic chemistry. In this field, dynamic kinetic resolution (DKR) and dynamic kinetic asymmetric transformation (DyKAT) have been demonstrated as highly effective tools in the enantioselective synthesis of atropisomeric biaryls, overcoming the limitation of kinetic resolution (KR) by pushing the theoretical yield of 50% to 100%. In this review, we summarize the development for the synthesis of optically active atropisomeric biaryls through a DKR or DyKAT route. Different racemization strategies have been developed and combined with a KR process to achieve the DKR of biaryls with hindered rotations. DyKAT is generally realized by a single catalytic system, accounting not only for epimerization of the axial chirality element in the intermediate but also for the control of enantioselectivity in the functionalization step. Finally, we discuss the limitations of existing methods and look forward to potential future research directions.