From Radical Coupling to Enantioselective Controlled Protonation: Advancing Precise Construction of Stereocenters.

Recent advancements in green and sustainable platforms, particularly visible light-driven photocatalysis, have spurred significant progress in radical chemistry, enabling the efficient synthesis of important molecules from simple and readily available feedstocks under mild conditions. However, the rapid orbital flipping and high reactivity of radicals pose substantial challenges for achieving precise enantiocontrol in stereocenter formation via radical coupling. In this study, we present a generic and efficient strategy that modulates this elusive approach, facilitating enantiocontrollable protonation through 1,3-boron migration. We successfully developed two previously elusive photocatalytic asymmetric transformations: the de Mayo reaction utilizing energy transfer and three-component reactions of cyanoazaarenes initiated by single-electron transfer. Moreover, the incorporation of cost-effective DO as a deuterium source enhances the synthetic and pharmaceutical significance of this method, offering a valuable tool for future applications.