Olefin Hydrogenation Enabled by a Nickel(‒II) Catalyst Precursor

The hydrogenation of olefins, including sterically hindered tri-substituted derivatives, was accomplished using the pre-catalyst dilithiumbis(cycloocta-1,5-diene)nickelate(-II) ( 1 ). This highly reduced complex 1 is one of the most active nickel catalyst precursors for the hydrogenation of C=C double bonds. The mild conditions tolerate hydroxyl, halide, ester, and lactone functionalities. Mechanistic studies, including reaction progress analyses, poisoning experiments, and multinuclear NMR monitoring, indicate that a heterotopic (nickel nanoparticle) catalyst is in operation that is formed by hydrogenolysis of 1 . The nanoparticles have been characterized by transmission electron microscopy.