Deep eutectic solvents meet safe, scalable and sustainable hydrogenations enabled by aluminum powder and Pd/C

A general, safe and scalable reductive protocol, based on the in situ generation of H 2 from aluminum and water, has been developed in deep eutectic solvents for the reduction of many organic compounds under Pd-catalysis. The methodology has been efficiently applied to the multigram-scale synthesis of benzindopyrine as an active pharmaceutical ingredient. The in situ generation of H 2 from aluminum powder and water/KOH enabled a general hydrogenation method in cholinium chloride/glycerol deep eutectic solvent under Pd/C catalysis.