Promotion Effect of Pd in the Ru/C-Catalyzed Hydrogenation of Benzofurans

The selective hydrogenation of benzofurans (BFs) over supported metal catalysts is of fundamental interest for producing biologically active and pharmacologically relevant chemicals. However, most supported metal catalysts are confronted with the dilemmas of activity and selectivity. Herein, we report that the deposition of a small amount of Pd on commercial Ru/C makes inactive Ru/C active in BF hydrogenation at low temperatures (e.g., 4 °C), and the selectivity to 2,3-dihydrobenzofuran as high as 92% was obtained. Systematic investigations show that the catalytic performance of Pd^Ru/C is attributed to the synergy of Pd and Ru, respectively, for the activation of H2 and BF and a significantly reduced energy barrier for the C1 (O–C1C2) addition step due to the interaction between BF and oxyphilic Ru. Besides, a series of bioactive compounds could be successfully produced by the hydrogenation of BF derivatives with Pd^Ru/C as a catalyst. This study provides insights into the activation of O-containing heteroaromatics by the incorporation of oxyphilic sites in supported metal catalysts