• Cellular Chemistry and Pharmacological Tools
• Sustainable Synthesis and Catalytic Technologies

Abstract: The field of bioorthogonal chemistry has revolutionized our ability to interrogate and manipulate biological systems at the molecular level. However, the range of chemical reactions that can operate efficiently in biological environments without interfering with the native cellular machinery, remains limited. In this context, the rapidly growing area of photocatalysis offers a promising avenue for developing new type of bioorthogonal tools. The inherent mildness, tunability, chemoselectivity, and external controllability of photocatalytic transformations make them particularly well-suited for applications in biological and living systems. This minireview summarizes recent advances in bioorthogonal photocatalytic technologies, with a particular focus on their potential to enable the selective generation of designed products within biologically relevant or living settings.

Abstract: NADH is a key redox mediator in biology and biocatalysis, yet its catalytic use in non-enzymatic synthetic chemistry remains largely unexplored. Here, we show that NADH can act as a substoichiometric reductive quencher in red-light photoredox catalysis, enabling a redox-neutral C(sp2)–H alkylation of acceptor heterocycles. This strategy reduces waste and leads to excellent yields and selectivity by suppressing overreduction. The reaction proceeds in air, under mild, aqueous-compatible conditions and operates in biorelevant media, establishing NADH as a cofactor for artificial red-light photoredox catalysis.