L-cysteine-modified Ag-based nanomaterials for asymmetric electrocarboxylation of aromatic ketones

To efficiently use CO₂ as a C1 source for the synthesize of high-value-added chiral carboxylic acid products, L-cysteine-modified silver-based nanomaterials (L-Cys-Ag) were prepared via a one-step reduction method in this study. The material exhibited excellent electrocatalytic performance in the asymmetric electrocarboxylation of acetophenone, achieving a yield of 73% and an enantiomeric excess value of 87%. Moreover, the material is stable and reusable. Comparisons of electrolysis results, open-circuit potential, and in-situ infrared spectroscopy reveal that CO₂^·- generated by CO₂ electroreduction on Ag will couple with the radical anion of acetophenone to achieve electrocarboxylation. Additionally, the modified L-cysteine not only inhibits the over-reduction of CO₂ but also anchors the two substrates via its carboxyl and amino groups, providing a chiral microenvironment that enables high enantioselectivity.