Transfer Hydrogenolysis of Aryl Halides and Other Hydrogen Acceptors by Formate Salts in the Presence of Pd/C Catalyst

Article abstract of DOI:10.1021/jo00021a034

The Pd/C-catalyzed transfer hydrogenolysis of aryl halides by formate salts in a triphase system requires the absorption of all three substrates, the aryl halide acceptor, the formate anion, and the water, to a single site on the catalyst surface in a specific order.This unique mechanism necessitates delicate optimization of reaction conditions.The affinity of various hydrogen acceptors to the catalyst was determined by competitive kinetic experiments to be in the decreasing order: iodobenzene > phenylacetylene > styrene > bromobenzene > nitrobenzene > chlorobenzene > fluorobenzene.The rate-determining step in the overall transfer-hydrogenation process is the adsorption of the donors to the catalyst.