Catalytic Asymmetric Reductive Azaarylation of Olefins via Enantioselective Radical Coupling

Visible-light-driven photocatalytic reductive azaarylation has been widely used to construct the important imine-containing azaarene derivatives. In addition to the direct use of various commercially available cyanoazaarenes as feedstocks, thesynthetic advantages include precise regioselectivity, high efficiency, mild reaction conditions, and good functional group tolerance.However, although many efficient reductive azaarylation methods have been established, the example of an enantioselective manneris still unmet, which most likely can be ascribed to the highly reactive radical coupling as the key step of forming stereocenters.Exploring the feasibility of enantiocontrol thus constitutes an attractive but highly challenging task. Here, we demonstrate that chiralhydrogen-bonding/photosensitizer catalysis is a viable platform as it enables the realization of thefirst enantioselective manifold. Avariety of acyclic and cyclic enones as the reaction partners are compatible with the dual catalyst system, leading to a wide array ofvaluable enantioenriched azaarene variants with high yields and ees. Regulating the types of chiral catalysts represents one of theimportant manners to success, in which several readily accessibleCinchonaalkaloid-derived bifunctional catalysts are introduced in asymmetric photochemical reactions.

Automated summary

Visible-light-driven photocatalytic reductive azaarylation is widely used for the construction of imine-containing azaarene derivatives. Although efficient methods have been established, enantioselective reactions remain a challenge. This study demonstrates the feasibility of chiral hydrogen-bonding/photosensitizer catalysis for achieving enantioselective reductive azaarylation, leading to valuable enantioenriched azaarene variants.