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A thiol substrate-promoted one-pot synthesis of a library of heteroaromatic compounds was developed.

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Seeking new chemo-catalytic routes to produce glyceric acid using renewable biomass-based sugar as feedstock is of significance but remains a big challenge due to a quite low yield (<5%). Herein, we prepare an MgO catalyst with an oxygen vacancy and explore a simple but robust MgO–NaBF4 system, achieving the selective production of glyceric acid from fructose with a high yield of 78.8% in an O2 atmosphere via chemo-catalysis at mild conditions (373 K), eliminating the use of strong inorganic alkalis and severe reaction conditions. As far as we know, this has the highest value among the state-of-the-art chemo-catalytic strategies. Evidenced by the isotope-probe experiment and theoretical calculation, it was revealed that MgO and NaBF4 exhibited pronounced cooperative effects. The hydroxyl group exposed on the MgO surface first facilitated the adsorption of fructose. With the assistance of MgO, B­(OH)4 – from NaBF4 hydrolysis preferentially combined with β-d-fructofuranose, as evidenced by 11B and 13C NMR spectroscopy, due to its strong electron-withdrawing ability, producing a complex which could easily undergo ring-opening reaction with an attack of OH– derived from the alkaline MgO. More importantly, the oxygen vacancies on the MgO surface subsequently assisted the C3–C4 cleavage in fructose by MgO species to produce a glyceraldehyde intermediate and activated O2 to oxidize glyceraldehyde, yielding glyceric acid. The conjunction of B­(OH)4 – with a glyceraldehyde intermediate or glyceric acid could also hinder its over-oxidation. The insights in this work might provide new chemo-catalytic approaches for glyceric acid production from renewable biomass.