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The mechanism of the cross-coupling of phenylboronic acid with acetic anhydride, a viable model of the widely used Suzuki reaction, has been studied by DFT calculations at the BP86/6-31G* level of theory. Two alternative catalytic cycles have been investigated, one starting from a neutral Pd(0)L₂ complex, the other from an anionic “Jutand-type” [Pd(0)L₂X]^- species. The reaction profiles are in good agreement with the experimental findings, as both pathways require only moderate activation energies. Both pathways are dominated by cis-configured square-planar palladium(II)diphosphine intermediates. Despite careful investigations, we did not find in this model reaction any evidence for five-coordinate palladium(II) intermediates, which are commonly believed to cause the profound effects of counterions in palladium-catalyzed transformations. Instead, our calculations suggest that the higher catalytic activity of …