Copper-Catalyzed\nAsymmetric C(sp<sup>3</sup>)–H\nBenzylation: Stereoselective Synthesis of Unnatural Aromatic Amino\nAcids

The general synthesis of chiral unnatural aromatic amino\nacids\nhas rarely been reported. We herein describe a visible light-promoted\ncopper-catalyzed enantioselective C(sp<sup>3</sup>)–H benzylation\nof glycine derivatives. The method demonstrated compatibility in coupling\nvarious <i>N</i>-hydroxyphthalimide (NHP) esters derived\nfrom aromatic acids with glycine derivatives, providing a general\nprotocol for synthesizing analogues of phenylalanine, tryptophan,\nand tyrosine. This protocol features mild conditions, high enantioselectivity,\nexcellent functional group tolerance, and important impacts on the\ndevelopment of peptide drugs.