Electro-acidic Catalytic Cascade Reactions for the Efficient and Highly Selective Synthesis of Oxygen Heterocyclic Compounds from Ethylene Glycol

The electrocatalytic selective oxidation of alcohol for direct heterocyclic ring compound production under ambient conditions is highly desirable but greatly challenging, due to the fast oxidation kinetics of aldehyde intermediate species during electrocatalysis. Here, for the first time, an electro-acidic catalytic cascade reaction strategy has been developed for the efficient and selective conversion from ethylene glycol to 1, 4-Dioxane-2, 5-diol under ambient conditions on synthesized CeO₂-e-Pd/CP electrocatalyst, which features a significantly high faraday efficiency of 83.6%. The CeO₂ in the electrocatalyst induces the downshift of the d-band center of Pd, which favors the fast desorption of glycolaldehyde from the electrocatalyst with ease into the acidic electrolyte, facilitating its subsequent condensation into 1, 4-Dioxane-2, 5-diol through C–O coupling while preventing the overoxidation of the glycolaldehyde intermediate into carboxylic acids. This work provides a novel strategy and insight into the reaction design for the synthesis of heterocyclic ring productions from simple molecules.