Control of selectivity in hydrosilane-promoted heterogeneous palladium-catalysed reduction of furfural and aromatic carboxides

The production of liquid fuels and fine chemicals often involves multi-step reaction processes with selective hydrogenation as one of the key steps. This step most often depends on high-pressure excess hydrogen gas, fossil resources, and newly prepared metallic catalysts. Here we describe an approach to tune activity and selectivity toward transfer hydrogenation of renewable biomass derivatives over commercially available Pd/C using liquid hydrosilane as hydrogen source. The appropriate control of water-doping content, acid type, reaction temperature, and liquid H− donor dosage permits the selective formation of four different value-added products in high yields (≥90%) from bio-based furfural under mild reaction conditions (15–100 °C). Mechanistic insights into the hydrosilane-mediated cascade reactions of furfural are obtained using isotope labeling. The catalyst is recyclable and can selectively reduce an extensive range of aromatic carbonyl compounds to the corresponding alcohols or hydrocarbons in 83–99% yield, typically at 25–40 °C.