Exploiting Photoredox Catalysis for Rapid Access to Unnatural α-Amino Acids through α-Amino C–H Bond Activation

Unnatural amino acids (UAAs) have shown great potential to enhance the pharmacological properties of peptides and represent a key motif in a wide range of biologically relevant natural products. Herein, we disclose a protocol that facilitates the asymmetric synthesis of UAAs from widely abundant amines through photoredox-mediated α-amino C–H bond activation. The platform utilizes either the strongly oxidizing organic acridinium or decatungstate as a photocatalyst to generate α-amino radicals from a variety of amines, which are then effectively coupled with a chiral glyoxylate-derived N-sulfinyl imine. The disclosed platform provides a general entry to various decorated unnatural α-amino acid derivatives, accommodating a diverse array of functional groups.