Modulation of ketyl radical reactivity to mediate the selective synthesis of coupling and carbonyl compounds

The importance of selective synthesis of high-value-added chemicals from renewable resources is paramount but remains a crucial challenge in organic synthesis and chemical reformation. Herein, we report the selective photosynthesis of C–C coupling products and carbonyl compounds from biomass-derived alcohols. The key to ensuring high end-to-end selectivity is the modulation of the reactivity of ketyl radical (*RCHOH) intermediates by employing different metal co-catalysts (Au, Pt, Pd, Ru) supported on Cd 0.6 Zn 0.4 S solid solution (CZS) photocatalysts . In particular, the C–C coupling product, hydrobenzion, and fully oxidized benzaldehyde were obtained from benzyl alcohol with high selectivity (> 98%) over Au-CZS and Ru-CZS, respectively. Combined experimental and theoretical analyses demonstrated that the affinity of *RCHOH for the surface of metals governs their subsequent transformations, in which weak and strong radical adsorption on Au and Ru results in C–C coupling products and carbonyl compounds , respectively. The biomass-derived alcohols on Au-CZS and Ru-CZS catalysts were converted to the corresponding C–C coupling products and carbonyl compounds, respectively, due to the different adsorption energies of • RCHOH intermediates on different metal surfaces.