How Photoredox Chemistry Turns Simple Amino Acids into Chiral Building Blocks?

The synthesis of enantioenriched, non-proteinogenic amino acids is central to modern medicinal chemistry, peptide science, and drug discovery. Traditional asymmetric approaches often require prefunctionalized substrates, multi-step sequences, or harsh reaction conditions that limit functional group tolerance. Photoredox catalysis has emerged as a powerful tool for generating radicals under mild conditions, yet controlling stereochemistry in radical-based amino acid functionalization remains a major challenge.

This study showcases how photoredox catalysis can be combined with asymmetric catalysis to achieve stereocontrolled radical transformations that are difficult or impossible using classical ionic chemistry. By providing a scalable, modular route to chiral amino acids from readily available starting materials, the work significantly expands the synthetic utility of photoredox methods in peptide and medicinal chemistry. It also demonstrates that photoredox catalysis is mature enough to support industrially relevant reaction formats such as flow chemistry.

While the substrate scope is broad, the reaction requires preactivation of amino acids, and extension to fully unprotected systems remains an open challenge. Additionally, the approach focuses on a specific radical generation mode, and its generality across other photoredox platforms has yet to be explored.