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 Cd0.6Zn0.4S 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. (c) 2024, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved..