Photochemical‐, Electrochemical‐, and Photoelectrochemical‐ Catalyzed Hydrogen Atom Transfer from Aldehydes to Acyl Radicals and Their Transformations

Acyl radical has assumed an eminent position in the synthetic chemistry due to its unique and often highly reactivity. Using aldehyde as acyl radical source does not require the prefunctionalization of substrate. Furthermore, the formation of acyl radical can be achieved through a hydrogen atom transfer (HAT) process. In recent years, photochemical‐, electrochemical‐, and photoelectrochemical‐catalyzed intermolecular HAT from aldehydes have been regarded as mild and sustainable routes to acyl radicals. Herein, we discuss the important advancements in the past 6 years in photo‐, electro‐, and photoelectro‐catalyzed generation of acyl radicals from aldehydes and their applications in organic synthesis. We also highlight the mechanistic insights that have emerged from these transformations.