[Pd(C^∧N)(X)(PPh₃)] palladacycles react with 2,4,6-trifluorophenyl boronic acid to give stable transmetallation products of the type [Pd(C^∧N)(2,4,6-F₃C₆H₂)(PPh₃)]

Abstract

Direct transmetallation between palladacyclic complexes and arylboronic acid occurs to give isolable transmetallation products. In THF, the reaction occurs <0.5 h. Prolonged reaction leads to the generation of a dinuclear Pd complex bearing bridging μ-hydroxo and μ-acetoxy ligands. Insight into precatalyst activation for Suzuki-Miyaura cross-couplings mediated by palladacycles has been gained, where acetate and N-imidate anions activate a neutral arylboronic acid.

Rationalization of the mechanism of in situ Pd(0) formation for cross-coupling reactions from novel unsymmetrical pincer palladacycles using DFT calculations

“…The formation of Pd(0), believed to occur prior to catalysis in SM cross-coupling reactions employing palladacycles [22,23,50], was investigated by considering the reaction of each pincer palladacycle with phenylboronic acid (Scheme 3). These energy barriers are in close agreement with literature precedents for the TM step of the SM reactions in the gas-phase without base [56].…”

Facile Hydrolysis and Alcoholysis of Palladium Acetate

“…Palladium(II) acetate is a ubiquitous precursor in an extremely wide range of synthetic and catalytic transformations, yet we show herein that in very many cases what is assumed to be palladium acetate is in fact not 1. This is because palladium acetate is highly sensitive to moisture in solution, reacting readily with low concentrations of water in a range of common organic solvents, including solvents that have been “dried” over calcium hydride, to give the structurally characterized complex [Pd 3 (μ 2 ‐OH)(OAc) 5 ] ( 1 ) 2. Similarly, reaction with alcohols generates the alkoxide complexes [Pd 3 (μ 2 ‐OR)(OAc) 5 ] 3 .…”

Kinetic Studies on the Palladium(II)‐Catalyzed Oxidative Cross‐Coupling of Thiophenes with Arylboron Compounds and Their Mechanistic Implications

“…Possible transition states that could lead to intermediates B or B′ are depicted in Figure 8. For the formation of B , that is, for the transmetalation of the phenyl group, it is conceivable that the boron atom of 2 is simultaneously activated by the trifluoroacetate anion 20i. An intramolecular reaction course can be envisioned for this process.…”