Electron / hole catalysis: A versatile strategy for promoting chemical transformations

Electron transfer is a fundamental chemical process that adds an electron into one chemical entity and generates a hole in another. Both the additional electron and the corresponding hole exhibit remarkable catalytic effects in promoting chemical transformations. In this Perspective, by classifying the implementation methods of electron/hole catalysis into four categories—namely, chemical, electrochemical, photochemical and mechanochemical means—we summarize the recent progress in this burgeoning field of research, focusing on the elegant ways that have been developed to inject or remove electrons into or from reaction systems under mild conditions. Moreover, recent advances in research involving the applications of electron/hole catalysis in molecular switches and supramolecular assemblies are also highlighted in order to show the versatility and potential of this strategy in all aspects of contemporary chemistry including, but not limited to, organic synthesis.