Mechanism of oxidative addition of palladium(0) with aromatic iodides in toluene, monitored at ultramicroelectrodes

Amatore, Christian; Pflüger, Fernando

doi:10.1021/om00158a026

Cited by 226 publications

(204 citation statements)

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“…The catalytically active palladium species is the low-ligated PdL 2 complex (L0monodentate phosphane ligand) or PdL 2 X -anion (X0Cl, Br, I) formed by the dissociation of stable PdL 4 catalyst. The dissociation equilibria of PdL 4 and its analogue NiL 4 have been investigated by Amatore et al and Tsou et al [26,27]. The mechanism of oxidative addition is strongly dependent on the reaction conditions and can change during the course of the reaction, as the halide anion can coordinate with lowligated palladium species and form a new active catalyst [28].…”

Section: Introductionmentioning

confidence: 99%

Computational study of the Sonogashira cross-coupling reaction in the gas phase and in dichloromethane solution

et al. 2011

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The Sonogashira cross-couplig reaction, consisting of oxidative addition, cis-trans isomerization, transmetalation, and reductive elimination, was computationally modeled using the DFT B3LYP/cc-pVDZ method for reaction between bromobenzene and phenylacetylene. Palladium diphosphane was used as a catalyst, copper(I) bromide as a co-catalyst and trimethylamine as a base. The reaction mechanism was studied both in the gas phase and in dichloromethane solution using PCM method. The complete catalytic cycle is thermodynamically strongly shifted toward products (diphenylacetylene and regenerated palladium catalyst) and is exothermic being in accordance with experimental data. The rate-determining step is the oxidative addition, since the highest point on the Gibbs energy graph of the complete reaction is the transition state of this step. This conclusion is also supported by recent experimental data. The computed energy profile suggests that the transmetalation step is initiated by the dissociation of neutral ligand, while the activation Gibbs energy of this step is 0.1 kcal mol(-1) in the gas phase.

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Section: Introductionmentioning

confidence: 99%

Computational study of the Sonogashira cross-coupling reaction in the gas phase and in dichloromethane solution

et al. 2011

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“…[95] Note that our values of DH°a nd DS°for the Sonogashira coupling are different from the DH°= 69 kJ mol À1 and DS°= À43 J mol À1 K as determined for the Heck coupling of acrylates. [96][97][98] This comes as no surprise as the cleavage of the much weaker C À I bond during the Heck reaction will be less significant for the overall rate of the catalytic cycle than the oxidative addition of the CÀCl bond. Consequently, the overall activation barrier can hardly be similar for aryl iodide Heck and the Sonogashira coupling reactions.…”

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confidence: 99%

Insights into Sonogashira Cross‐Coupling by High‐Throughput Kinetics and Descriptor Modeling

Heiden

Plenio

Immel

et al. 2008

Chemistry A European J

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A method is presented for the high-throughput monitoring of reaction kinetics in homogeneous catalysis, running up to 25 coupling reactions in a single reaction vessel. This method is demonstrated and validated on the Sonogashira reaction, analyzing the kinetics for almost 500 coupling reactions. First, one-pot reactions of phenylacetylene with a set of 20 different meta- and para-substituted aryl bromides were analyzed in the presence of 17 different Pd-phosphine complexes. In addition, the temperature-dependent Sonogashira reactions were examined for 21 different ArX (X=Cl, Br, I) substrates, and the corresponding activation enthalpies and entropies were determined by means of Eyring plots: ArI (DeltaH(not equal)=48-62 kJ mol(-1); DeltaS(not equal)=-71--39 J mol(-1) K; NO(2)-->OMe), ArBr (DeltaH(not equal)=54-82 kJ mol(-1), DeltaS(not equal)=-55-11 J mol(-1) K), and ArCl (DeltaH(not equal)=95-144 kJ mol(-1), DeltaS(not equal)=-6-100 J mol(-1) K). DFT calculations established a linear correlation of DeltaH( not equal) and the Kohn-Sham HOMO energies of ArX (X=Cl, Br, I) and confirmed their involvement in the rate-limiting step. However, despite different C--X bond energies, aryl iodides and electron-deficient aryl bromides showed similar activation parameters.

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“…Accurate computer calculations of such large complexes need an extremely large computational cost. Additionally, for palladium catalysts based on regular bidentate ligands (e.g., BINAP (I) [31]) and monodentate ligands (e.g., oligo-aryl phosphine (II) and oligo-aryl phosphonites (III) [32]) (Figure 1), several different models of solvation and mono-and biscomplexation should be evaluated [23,[33][34][35][36]. Obviously, a discovery of subtle interactions influencing the absolute configuration of the product formed in the reaction mediated by interconverting complexes of large phosphorus ligands cannot be accurate because of many entropic issues that certainly take place but are difficult to handle.…”

Section: Methodsmentioning

confidence: 99%

A Quantum-Chemical DFT Approach to Elucidation of the Chirality Transfer Mechanism of the Enantioselective Suzuki–Miyaura Cross-Coupling Reaction

Jasiński

Demchuk

Babyuk

2017

Journal of Chemistry

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The DFT calculations of the simplified model of the asymmetric Suzuki-Miyaura coupling reaction were performed at the M062x/LANL2DZ theory level at first. It was found that enantioselective reactions mediated by the palladium complexes of chiral C,P-ligands follow a four-stage mechanism similar to that proposed previously as one of the most credible mechanisms. It should be underlined that the presence of substituents in the substrates and the chiral ligand at ortho positions determines the energies of possible diastereoisomeric transition states and intermediates in initial reaction steps. This suggests that, in practice, a sharp selection of theoretically possible paths of chirality transfer from the catalyst to the product should have a place and, therefore, the absolute configuration of the formed atropisomeric product is defined and can be predicted.

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Mechanism of oxidative addition of palladium(0) with aromatic iodides in toluene, monitored at ultramicroelectrodes

Cited by 226 publications

References 0 publications

Computational study of the Sonogashira cross-coupling reaction in the gas phase and in dichloromethane solution

Computational study of the Sonogashira cross-coupling reaction in the gas phase and in dichloromethane solution

Insights into Sonogashira Cross‐Coupling by High‐Throughput Kinetics and Descriptor Modeling

A Quantum-Chemical DFT Approach to Elucidation of the Chirality Transfer Mechanism of the Enantioselective Suzuki–Miyaura Cross-Coupling Reaction

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