Synthesis of 13C-labeled α-Amino Acids via Visible Light-Driven C(sp3)–H Carboxylation with 13C-Formate

The 13C-labeled α-amino acids are important molecules in biological study and drug development. Cost-effective synthesis of α-amino acids with high 13C-incorporation under mild conditions remains limited. Herein, we report the development of a C(sp3)–H carboxylation method to prepare 13C-labeled α-amino acids using near-stoichiometric and user-friendly sodium 13C-formate. A series of phenylglycine derivatives with excellent 13C-incorporation were prepared efficiently. The sequential reaction path-way of in situ 13CO2 generation followed by C–H carboxylation via 1,2-HAT was suggested by mechanistic studies. This meth-od provides a novel access to 13C-labeled amino acids that could be used in many fields such as drug development and medical studies.