Effect of Halide Ligands on the Reactivity of Carbon−Palladium Bonds:  Implications for Designing Catalytic Reactions

Abstract

The integral role of halide ions as a ligand in divalent palladium-catalyzed nucleophile−alkyne−α,β-unsaturated carbonyl coupling reaction as well as in the stoichiometric reaction of arylpalladium reagents with acrolein was studied. Excess of halide ions can effectively inhibit the β-hydride elimination of a (2-oxoalkyl)palladium intermediate, giving preferentially the protonolysis product in acidic media. This result may have further implications for the design and development of divalent palladium-catalyzed reactions