Harnessing Visible Light: Photocatalyzed Green Routes to Complex Heterocycles (2019–2024)

Abstract The drug development process demands synthetic strategies that are green, sustainable, and provide reliable access to diverse areas of chemical space. Historically, drug discovery programs have relied on transition metal‐catalyzed two‐electron chemistry to form new bonds. However, rapid advances in photocatalysis have led to the discovery of numerous new reactivity modes and enabled precise late‐stage functionalization of complex molecular scaffolds used extensively in medicinal chemistry and pharmaceutical research. This review highlights recent progress in the synthesis and derivatization of drug‐like heterocycles using photocatalysis (e.g., Ir, Ru, Rh), with particular emphasis on novel transformations reported in the past five years. These photocatalysts possess photophysical and photochemical characteristics that allow for efficient energy transfer and the production of radicals when exposed to visible light.