Divergent Reactivity of Stannane and Silane in the Trifluoromethylation of Pd<sup>II</sup>: Cyclic Transition State versus Difluorocarbene Release

Pu, Maoping; Sanhueza, Italo A.; Senol, Erdem; Schoenebeck, Franziska

doi:10.1002/anie.201808229

Cited by 28 publications

(23 citation statements)

References 76 publications

(29 reference statements)

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“…It is interesting here to compare the mechanism shown in Scheme 3 with the one obtained by Schoenebeck and coworkers for the transmetalation of [Pd II ]−F complexes with the Ruppert−Prakash reagent 8 to yield [Pd II ]−CF 3 intermediates. 19 In that case, the calculations showed that the reaction proceeds through a short-lived Pd-difluorocarbene intermediate.…”

Section: Resultsmentioning

confidence: 98%

Mechanisms of Formation and Rearrangement of Benziodoxole-Based CF₃ and SCF₃ Transfer Reagents

2020

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Togni’s benziodoxole-based reagents are widely used in trifluoromethylation reactions. It has been established that the kinetically stable hypervalent iodine form (I–CF3) of the reagents is thermodynamically less stable than its acyclic ether isomer (O–CF3). On the other hand, the trifluoromethylthio analogue exists in the thermodynamically stable thioperoxide form (O–SCF3), and the hypervalent form (I–SCF3) has been elusive. Despite the importance of these reagents, very little is known about the reaction mechanisms of their syntheses, which has hampered the development of new reagents of the same family. Herein, we use density functional theory calculations to understand the reasons for the divergent behaviors between the CF3 and SCF3 reagents. We demonstrate that they follow different mechanisms of formation and that the metals involved in the syntheses (potassium in the case of the trifluoromethyl reagent and silver in the trifluoromethylthio analogue) play key roles in the mechanisms and greatly influence the possibility of their rearrangements from the hypervalent (I–CF3, I–SCF3) to the corresponding ether-type form (O–CF3, O–SCF3).

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Section: Resultsmentioning

confidence: 98%

Mechanisms of Formation and Rearrangement of Benziodoxole-Based CF₃ and SCF₃ Transfer Reagents

2020

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“…In 2018, Schoenebeck reported a decarbonylative trifluoromethylation of aroyl fluorides utilizing a Pd/Xantphos catalyst system and TESCF 3 as the trifluoromethyl source. 29 By computational methods, they proposed that the Pd(II) acyl complex (Xantphos)Pd(COPh)F is an intermediate efficiently undergoing transmetalation with TESCF 3 without external activation to form (Xantphos)Pd(COPh)CF 3 . Moreover, they found the activation energy for the reductive elimination step from this Pd(II)−CF 3 acyl complex to be lower than that for a decarbonylation.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…19 F NMR (376 MHz, CD 2 Cl 2 ): δ (ppm) −17.0 (t, J = 13.6 Hz, 3F). 31 P and 19 F NMR spectra are consistent with literature data. , …”

Section: Methodsmentioning

confidence: 99%

Stoichiometric Studies on the Carbonylative Trifluoromethylation of Aryl Pd(II) Complexes using TMSCF₃ as the Trifluoromethyl Source

et al. 2020

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We have performed a series of stoichiometric studies in order to identify viable steps for a hypothetical catalytic cycle for the palladium-mediated carbonylative coupling of an aryl bromide with TMSCF3. Our work revealed that benzoyl Pd(II) complexes bearing Xantphos or tBu3P as the phosphine ligands, which are generated from the corresponding PdII(Ph)Br complexes exposed to stoichiometric 13CO from 13COgen, were unable to undergo transmetalation and reductive elimination to trifluoroacetophenone. Instead, in the presence of base and additional CO, these organometallic complexes readily underwent reductive elimination to the acid fluoride. Attempts to determine whether the acid fluoride could represent an intermediate for acetophenone production were unrewarding. Only in the presence of a boronic ester did we observe some formation of the desired product, although the efficiency of transformation was still low. Finally, we investigated the reactivity of four phosphine-ligated PdII(Ph)CF3 complexes (Xantphos, DtBPF, tBu3P, and triphenylphosphine) with carbon monoxide. With the exception of the tBu3P-ligated complex, all other metal complexes led to the facile formation of trifluoroacetophenone. We also determined in the case of triphenylphosphine that CO insertion occurred into the Pd–Ar bond, as trapping of this complex with n-hexylamine led to the formation of n-hexylbenzamide.

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“…[128][129][130][131] In such scenarios, Born-Oppenheimer molecular dynamics (BOMD) calculations on the QM-calculated PES can be used to generate a statistically representative number of trajectories from the transition states, as well as to monitor the dynamics of reactive events of relevant metal species. 132 In addition, quasi-classical molecular dynamics has been applied with great success in both organic reactions with bifurcation points and homogeneous transition metal catalysis. [133][134][135] For smaller systems, ab initio molecular dynamics (AIMD) can also be utilized.…”

Section: Study Of Ground-state and Excited-state Dynamical Behaviormentioning

confidence: 99%

Mechanisms, challenges, and opportunities of dual Ni/photoredox‐catalyzed C(sp²)–C(sp³) cross‐couplings

Yuan

Gutiérrez

2021

WIREs Comput Mol Sci

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The merging of photoredox and nickel catalysis has revolutionized the field of C–C cross‐coupling. However, in comparison to the development of synthetic methods, detailed mechanistic investigations of these catalytic systems are lagging. To improve the mechanistic understanding, computational tools have emerged as powerful tools to elucidate the factors controlling reactivity and selectivity in these complex catalytic transformations. Based on the reported computational studies, it appears that the mechanistic picture of catalytic systems is not generally applicable, but is rather dependent on the specific choice of substrate, ligands, photocatalysts, etc. Given the complexity of these systems, the need for more accurate computational methods, readily available and user‐friendly dynamics simulation tools, and data‐driven approaches is clear in order to understand at the molecular level the mechanisms of these transformations. In particular, we anticipate that such improvement of theoretical methods will become crucial to advance the understanding of excited‐state properties and dynamics of key species, as well as to enable faster and unbiased exploration of reaction pathways. Further, with greater collaboration between computational, experimental, and spectroscopic communities, the mechanistic investigation of photoredox/Ni dual‐catalytic reactions is expected to thrive quickly, facilitating the design of novel catalytic systems and promoting our understanding of the reaction selectivity. This article is categorized under: Structure and Mechanism > Reaction Mechanisms and Catalysis Electronic Structure Theory > Density Functional Theory Molecular and Statistical Mechanics > Molecular Dynamics and Monte‐Carlo Methods

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Divergent Reactivity of Stannane and Silane in the Trifluoromethylation of Pd^II: Cyclic Transition State versus Difluorocarbene Release

Cited by 28 publications

References 76 publications

Mechanisms of Formation and Rearrangement of Benziodoxole-Based CF₃ and SCF₃ Transfer Reagents

Mechanisms of Formation and Rearrangement of Benziodoxole-Based CF₃ and SCF₃ Transfer Reagents

Stoichiometric Studies on the Carbonylative Trifluoromethylation of Aryl Pd(II) Complexes using TMSCF₃ as the Trifluoromethyl Source

Mechanisms, challenges, and opportunities of dual Ni/photoredox‐catalyzed C(sp²)–C(sp³) cross‐couplings

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Divergent Reactivity of Stannane and Silane in the Trifluoromethylation of PdII: Cyclic Transition State versus Difluorocarbene Release

Cited by 28 publications

References 76 publications

Mechanisms of Formation and Rearrangement of Benziodoxole-Based CF3 and SCF3 Transfer Reagents

Mechanisms of Formation and Rearrangement of Benziodoxole-Based CF3 and SCF3 Transfer Reagents

Stoichiometric Studies on the Carbonylative Trifluoromethylation of Aryl Pd(II) Complexes using TMSCF3 as the Trifluoromethyl Source

Mechanisms, challenges, and opportunities of dual Ni/photoredox‐catalyzed C(sp2)–C(sp3) cross‐couplings

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Divergent Reactivity of Stannane and Silane in the Trifluoromethylation of Pd^II: Cyclic Transition State versus Difluorocarbene Release

Mechanisms of Formation and Rearrangement of Benziodoxole-Based CF₃ and SCF₃ Transfer Reagents

Mechanisms of Formation and Rearrangement of Benziodoxole-Based CF₃ and SCF₃ Transfer Reagents

Stoichiometric Studies on the Carbonylative Trifluoromethylation of Aryl Pd(II) Complexes using TMSCF₃ as the Trifluoromethyl Source

Mechanisms, challenges, and opportunities of dual Ni/photoredox‐catalyzed C(sp²)–C(sp³) cross‐couplings