Levulinic Acid Hydrogenation with Homogeneous Cu(I) Catalyst

We report the first well-defined homogeneous copper-based catalyst for levulinic acid (LVA) hydrogenation using complex [(PPh3)(2)Cu(k(2)-O,O-LVA)] as a copper source and (1,2-bis(diisopropyl phosphino)ethane (dippe) as an ancillary ligand. This catalytic precursor has high activity in LVA hydrogenation and yields gamma-valerolactone (GVL) under relatively mild reaction conditions (24 h, 140 degrees C) in a base-free system using H-2 (300 psi) as a reductant. Under optimized conditions, GVL was obtained with excellent yield (>99 %) and selectivity (>99 %) using a low catalytic load (0.025 mol %), allowing a TON=4000.