Striding the threshold of an atom era of organic synthesis by single-atom catalysis

The bigger pictureThe advent of single-atom catalysts (SACs) brings atomic ideas to organic synthesis. Regrettably, although many useful organic reactions have been achieved by using SACs so far, most of the research still follows the research mode of electrocatalysis. This also limits the use of SACs to improving catalytic activity and selectivity. In addition to the reported latest development in the field of organic synthesis involving SACs in the past 10 years, this review discusses the reaction mechanism, the structure-activity relationship is clarified, and the catalytic nature and uses of SACs in the synthesis reaction are summarized. It is foreseeable that the research of SACs in organic synthesis will gradually follow the research model of synthesis methodology. In addition, more efforts should be made toward using their structure features to create new organic reactions as well as understanding the mechanism of reactions.SummaryIn the history of synthesis, people applied heat, electricity, and other means to expand the synthesis field, thus promoting the construction of the magnificent material world. However, with the time passing, beyond the synthetic methods used in a laboratory, are there other solutions? The arising concept of single-atom catalysts (SACs) expands synthesis to the atomic scale. Through the fine-tuned and atom-level methods, people can obtain a catalytic scheme completely different from homogeneous catalysis, ultimately realizing the high-efficient, economical, and precise catalysis of synthesis. In this review, we focus on the latest development of synthesis involving SACs in the past 10 years. By discussing the reaction mechanism and combining the advantages of SACs, the structure-activity relationship is clarified, and the catalytic nature and general uses of SACs in the synthesis are summarized. Finally, we propose the opportunities, challenges, and development directions of SACs in organic synthesis in the next step.Graphical abstract