Recent Progress on Organic Electron Donors (OEDs) Enabled Radical Reactions

Abstract Over the past few decades, organic transformations facilitated by small organic molecules have witnessed considerable advancements. Small organic molecules have been widely applied to the construction of various skeletons. However, reduction as one of the fundamental reactions is generally initiated by metal‐containing reducing agents, although the initial progress of organic electron donors (OEDs) enabled reductive cleavage of some chemical bonds had been achieved in 1990s. Due to their structural diversity and tunability, OEDs can overcome the limitations of metal‐based reducing agents, such as low selectivity and poor functional group tolerance as well as the environmental problems caused by substantial inorganic waste after reactions. Building on a brief historical overview of OED research, this review focuses on the rencent advancements of the OEDs promoted radical reactions. It covers the reduction of C−X (X=C, O, N etc.) single bonds, radical cyclization, intermolecular radical addition to unsaturated bonds, radical coupling, functionalization of aromatics, and C−H bond activation. Additionally, the mechanistic insights of the typical reactions are highlighted for well understanding of the reaction mode involving OEDs.