Transfer Hydrogenation Of Levulinic Acid To Gamma-Valerolactone And Pyrrolidones Using A Homogeneous Nickel Catalyst

We report a well-defined homogeneous nickel-based catalyst using the complex [dippeNi(COD)] (dippe=1,2-bis(diisopropyl phosphino)ethane) as a catalytic precursor with high activity in the hydrogenation of levulinic acid (LVA) to yield gamma-valerolactone (GVL) under relatively mild conditions (4 h, 120 degrees C); formic acid (FA) is the transfer hydrogenation agent in a dehydrogenation-hydrogenation process. Under optimized conditions, GVL was obtained with excellent yield (>99 %) and selectivity (>99 %). The Ni-catalyst was assessed in the LVA hydrogenation with a variety of primary amines using an excess of FA (4 eq) as hydrogen donor at 15 h and 170 degrees C to produce 2-pyrrolydones with excellent yield (>99 %) and fair to good selectivity (from 68 to 92 %).