A Density Functional Theory Study of the Stille Cross‐Coupling <i>via</i> Associative Transmetalation. The Role of Ligands and Coordinating Solvents

Faza, Olalla Nieto; Lera, Ángel R. de; Cárdenas, Diego J.

doi:10.1002/adsc.200600312

Cited by 43 publications

(4 citation statements)

References 63 publications

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“…Besides, from eqs and , we know that the influence of the intermediates is equally significant (and easier to study , ). Moreover, as the TDI and TDTS are not necessarily adjoined (as in Figure ), , several steps can participate in the shaping of the kinetics. ,,− Therefore, there are no rate determining STEPS, but rate determining STATES!…”

Section: Reviewing Kinetic Terminology For Catalytic Cyclesmentioning

confidence: 99%

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How to Conceptualize Catalytic Cycles? The Energetic Span Model

2010

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A computational study of a catalytic cycle generates state energies (the E-representation), whereas experiments lead to rate constants (the k-representation). Based on transition state theory (TST), these are equivalent representations. Nevertheless, until recently, there has been no simple way to calculate the efficiency of a catalytic cycle, that is, its turnover frequency (TOF), from a theoretically obtained energy profile. In this Account, we introduce the energetic span model that enables one to evaluate TOFs in a straightforward manner and in affinity with the Curtin-Hammett principle. As shown herein, the model implies a change in our kinetic concepts. Analogous to Ohm's law, the catalytic chemical current (the TOF) can be defined by a chemical potential (independent of the mechanism) divided by a chemical resistance (dependent on the mechanism and the nature of the catalyst). This formulation is based on Eyring's TST and corresponds to a steady-state regime. In many catalytic cycles, only one transition state and one intermediate determine the TOF. We call them the TOF-determining transition state (TDTS) and the TOF-determining intermediate (TDI). These key states can be located, from among the many states available to a catalytic cycle, by assessing the degree of TOF control (X(TOF)); this last term resembles the structure-reactivity coefficient in classical physical organic chemistry. The TDTS-TDI energy difference and the reaction driving force define the energetic span (δE) of the cycle. Whenever the TDTS appears after the TDI, δE is the energy difference between these two states; when the opposite is true, we must also add the driving force to this difference. Having δE, the TOF is expressed simply in the Arrhenius-Eyring fashion, wherein δE serves as the apparent activation energy of the cycle. An important lesson from this model is that neither one transition state nor one reaction step possess all the kinetic information that determines the efficiency of a catalyst. Additionally, the TDI and TDTS are not necessarily the highest and lowest states, nor do they have to be adjoined as a single step. As such, we can conclude that a change in the conceptualization of catalytic cycles is in order: in catalysis, there are no rate-determining steps, but rather rate-determining states. We also include a study on the effect of reactant and product concentrations. In the energetic span approximation, only the reactants or products that are located between the TDI and TDTS accelerate or inhibit the reaction. In this manner, the energetic span model creates a direct link between experimental quantities and theoretical results. The versatility of the energetic span model is demonstrated with several catalytic cycles of organometallic reactions.

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Section: Reviewing Kinetic Terminology For Catalytic Cyclesmentioning

confidence: 99%

“…Moreover, as the TDI and TDTS are not necessarily adjoined (as in Figure 12), 26,27 several steps can participate in the shaping of the kinetics. 9,25,[51][52][53] Therefore, there are no rate determining STEPS, but rate determining STATES!…”

Section: Reviewing Kinetic Terminology For Catalytic Cyclesmentioning

confidence: 99%

How to Conceptualize Catalytic Cycles? The Energetic Span Model

2010

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“…35 Computational studies concluded that the ligand assisted mechanism was energetically the most favored. 36 The isomerization of the oxidative addition product cis-Pd(II)L 2 RX to trans-Pd(II)L 2 RX complex is usually very fast 37 and therefore, the trans-complex is generally accepted as the starting point of the deprotonation step. The next step in the Pd-catalyzed cycle would connect with the cycle of the Cu co-catalyst.…”

Section: Copper Co-catalyzed Reaction Mechanismmentioning

confidence: 99%

Recent mechanistic developments and next generation catalysts for the Sonogashira coupling reaction

Karak

Barbosa

Hargaden³

2014

RSC Adv.

130

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“…With new advances in theoretical methods and increased computational power, computational tools have become an important method for elucidating reaction mechanisms and the origin of various selectivities in transition‐metal‐catalyzed organic reactions . Although numerous computational studies about the mechanism of palladium‐catalyzed carbon–carbon cross‐coupling reactions, such as Suzuki–Miyaura coupling, Heck coupling, Sonogashira cross‐coupling, Stille coupling, and Hiyama coupling, have been reported, those about the palladium‐catalyzed silicon–carbon coupling reaction are still rare . To the best of our knowledge, no theoretical studies are available for the title reaction.…”

Section: Introductionmentioning

confidence: 99%

Mechanistic Insights into Palladium‐Catalyzed Silylation of Aryl Iodides with Hydrosilanes through a DFT Study

Zhang

et al. 2017

Chemistry An Asian Journal

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The catalytic cycles of palladium-catalyzed silylation of aryl iodides, which are initiated by oxidative addition of hydrosilane or aryl iodide through three different mechanisms characterized by intermediates R Si-Pd -H (Cycle A), Ar-Pd -I (Cycle B), and Pd (Cycle C), have been explored in detail by hybrid DFT. Calculations suggest that the chemical selectivity and reactivity of the reaction depend on the ligation state of the catalyst and specific reaction conditions, including feeding order of substrates and the presence of base. For less bulky biligated catalyst, Cycle C is energetically favored over Cycle A, through which the silylation process is slightly favored over the reduction process. Interestingly, for bulky monoligated catalyst, Cycle B is energetically more favored over generally accepted Cycle A, in which the silylation channel is slightly disfavored in comparison to that of the reduction channel. Moreover, the inclusion of base in this channel allows the silylated product become dominant. These findings offer a good explanation for the complex experimental observations. Designing a reaction process that allows the oxidative addition of palladium(0) complex to aryl iodide to occur prior to that with hydrosilane is thus suggested to improve the reactivity and chemoselectivity for the silylated product by encouraging the catalytic cycle to proceed through Cycles B (monoligated Pd catalyst) or C (biligated Pd catalyst), instead of Cycle A.

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A Density Functional Theory Study of the Stille Cross‐Coupling via Associative Transmetalation. The Role of Ligands and Coordinating Solvents

Cited by 43 publications

References 63 publications

How to Conceptualize Catalytic Cycles? The Energetic Span Model

How to Conceptualize Catalytic Cycles? The Energetic Span Model

Recent mechanistic developments and next generation catalysts for the Sonogashira coupling reaction

Mechanistic Insights into Palladium‐Catalyzed Silylation of Aryl Iodides with Hydrosilanes through a DFT Study

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