Direct and Quantitative Formation of 2,5-Diethoxymethylfuran from HMF via Hybrid Catalytic Hydrogenation by Using a Ru-PNP Catalyst and Acid-Catalyzed Etherification in Ethanol

This study presents an integrated catalytic system enabling the quantitative production of 2,5-diethoxymethylfuran from HMF through a hybrid sequence that combines Ru-PNP-catalyzed hydrogenation with heterogeneous acid-catalyzed etherification in ethanol. The approach provides complete selectivity under mild conditions and demonstrates the compatibility of homogeneous hydrogenation catalysts with solid acid co-catalysts in a single process environment. In addition, we report the first example of homogeneously catalyzed hydrogenative valorization of HMF employing a co-catalytic, potentially recyclable acid additive. This strategy expands the scope of HMF upgrading pathways and highlights the potential of hybrid catalytic systems for the efficient synthesis of stable, energy-dense furan derivatives relevant to biofuel and biobased chemical applications.