Profiling the Privileges of Pyrrolidine-Based Catalysts in Asymmetric Synthesis: From Polar to Light-Driven Radical Chemistry

Asymmetric catalysis is a rapidly evolving field in synthetic chemistry. This is due to the growing needs of stereoselective synthetic routes to access enantiopure natural products and bioactive molecules. An efficient approach involves the use of readily available and robust catalysts, while ensuring high yields and stereocontrol. In this scenario, the pyrrolidine-based catalyst has played a dominant role over the past decades. Interestingly, simple scaffold modifications result in dramatic physicochemical and reactivity changes. These features have facilitated the generation of different catalyst variants for the development of highly diversified asymmetric transformations. In this Perspective, we analyze the structural evolution of the pyrrolidine-based catalyst, moving from polar to light-induced radical processes. We discuss the concepts underpinning the most relevant scaffold modifications while defining structure reactivity relationships. The present work will encourage a rational scaffold design toward unprecedented reactivity pathways and improved catalytic performances.