Palladium-catalyzed hydrogenation with use of ionic liquid bis(2-hydroxyethyl)ammonium formate [BHEA][HCO₂] as a solvent and hydrogen source

We designed ionic liquid bis(2-hydroxyethyl)ammonium formate [BHEA][HCO₂] for use as a solvent and hydrogen donor for hydrogenation. Catalytic hydrogenation of aromatic ketones, nitro groups, and olefins with PdCl₂ in [BHEA][HCO₂] generated the corresponding reduction products. Selective reduction of aromatic ketones over aliphatic ketones was observed. Hydrogenolysis of benzyl ethers and benzyl amines also proceeded. All these reactions were successfully carried out in good to excellent yields under mild and nonflammable conditions. In addition, the ionic liquid and Pd source can be reused several times.