A Sustainable Approach to Selective Hydrogenation of Unsaturated Esters and Aldehydes with Ruthenium Catalysts

The reduction of esters and aldehydes to alcohols is an important reaction in the chemical industry to produce a wide range of bulk and fine chemicals. Herein, the unexpected behavior of three state-of-the-art, commercially available Ru-catalysts for the hydrogenation of these feedstocks is reported. For ester and aldehydes containing a C=C bond, it was possible to carry out the selective hydrogenation of the ester or aldehyde functionality while keeping the C=C double-bond essentially untouched. Furthermore, it is demonstrated that these substrates can be reduced under very mild reaction conditions (as low as 40 degrees C and 5 bar of H-2) and that anisole, a solvent with a high sustainability rank, is suitable for these catalytic hydrogenations.