Precise construction of spiro stereocenters enantioselective radical addition through modulating photocatalysis from redox to energy transfer.

Chiral hydrogen-bonding catalysis has been successfully applied in a wide range of asymmetric photocatalytic radical-based reactions. However, it faces intrinsic challenges in the reactions that rely on oxidative quenching to initiate transformations. A critical issue arises from the formation of anionic side intermediates, which preferentially interact with protons from chiral catalysts, undermining the essential enantiocontrol required for effective product formation.