Visible light induced α-amino acid synthesis from carbon dioxide using nanostructured ZnO/CuO heterojunction photocatalyst

Light assisted activation of carbon dioxide for the carboxylation reactions has come out to be a sustainable approach for the synthesis of carboxylic acids under mild conditions. In the present work, we describe an efficient and green approach from the coupling of CO2 and amines to alpha-amino acids using a nanostructured ZnO-CuO heterojunction semiconductor photocatalyst under visible light irradiation. The developed protocol provided the selective alpha-carboxylation of different amine substrates bearing various functional groups and afforded moderate yields of corresponding carboxylated products. The photocatalyst could easily be recovered from the reaction mixture and reused for at least five runs without any vital loss in activity.