Palladium-Catalyzed <i>Meta</i>-Selective C–H Bond Activation with a Nitrile-Containing Template: Computational Study on Mechanism and Origins of Selectivity

Yang, Yun‐Fang; Cheng, Gui‐Juan; Liu, Peng; Leow, Dasheng; Sun, Tianyu; Chen, Ping; Zhang, Xinhao; Yu, Jin‐Quan; Wu, Yun‐Dong; Houk, K. N.

doi:10.1021/ja410485g

Cited by 342 publications

(152 citation statements)

References 110 publications

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“…Yu undertook a study to explain the observed meta selectivity in Pd-and Ag-catalyzed directed C−H activation reaction using the M06/6-311+ +G(d,p)(SDD)//B3LYP/6-31G(d)(LANL2DZ) methodology (Scheme 15a). 272 Some of their results were also validated against MP2 and CCSD(T) calculations. The selectivity was reached through a Pd−Ag heterodimeric complex, which while coordinated to the nitrile directing group places an acetate anion next to the meta C−H position.…”

Section: C−h Bond Activationmentioning

confidence: 97%

Computational Studies of Synthetically Relevant Homogeneous Organometallic Catalysis Involving Ni, Pd, Ir, and Rh: An Overview of Commonly Employed DFT Methods and Mechanistic Insights

et al. 2015

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Section: C−h Bond Activationmentioning

confidence: 97%

Computational Studies of Synthetically Relevant Homogeneous Organometallic Catalysis Involving Ni, Pd, Ir, and Rh: An Overview of Commonly Employed DFT Methods and Mechanistic Insights

et al. 2015

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“…This is also consistent with the experimentally observed meta selectivity with barriers for activation at the ortho and para positions being slightly higher, by 0.9 and 0.5 kcal mol −1 , respectively. In a related study, the meta-selective C-H activation of 18 by a Pd(OAc) 2 /AgOAc catalytic system was probed with M06(DCE)//B3LYP calculations (Figure 1.7b) [23]. A heterobimetallic PdAg(OAc) 3 6 , 37.9 kcal mol −1 ); moreover, for the monomeric and trimeric systems, an ortho selectivity was predicted.…”

Section: Early Computational Studiesmentioning

confidence: 98%

Computational Studies of Heteroatom‐Assisted CH Activation at Ru, Rh, Ir, and Pd as a Basis for Heterocycle Synthesis and Derivatization

Carr¹,

Macgregor²,

McMullin³

2016

Transition Metal‐Catalyzed Heterocycle Synthesis via CH Activation

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IntroductionModern computational chemistry is a key tool by which insight into organometallic reaction mechanisms can be gained. The ability to characterize short-lived intermediates and transition states provides an ideal complement to experiment, where such information is often extremely difficult, if not impossible, to obtain. Recent years have seen great advances in understanding the mechanisms of C-H bond activation, and this area was the subject of several major reviews toward the end of the last decade [1,2]. More recently, the focus has shifted to how C-H activation can be integrated into catalytic cycles for useful organic transformations. The C-H bond activation event is itself mechanistically diverse, with oxidative addition (OA), σ-bond metathesis (SBM), and electrophilic activation (EA) all potentially available at late transition metal centers, depending on the metal, its oxidation state, and the coordination environment. C-H activation assisted by a heteroatom base (typically a carboxylate or carbonate) falls into the last of these categories and forms the focus of this chapter. More recently, computational studies of catalytic cycles for C-H activation and functionalization have become more common. These reveal the complexity of what are usually multiple-step processes, and calculations are particularly well placed to test different mechanistic possibilities. Such studies are most effectively pursued through a close interaction between experiment and computation, and increasingly this is allowing for a more quantitative assessment of computed reaction mechanisms.As well as progress in mechanistic understanding, the last 10 years have seen important developments in the computational methodologies available to model transition metal reactivity. While density functional theory (DFT) remains the core method of choice, the ability to model larger systems that more closely reflect experiment has highlighted the known shortcomings of DFT in describing dispersion interactions. These long-range, stabilizing interactions are individually weak, but their cumulative effect in large systems can be significant. Methods to incorporate this component include its separate calculation (e.g., Transition Metal-Catalyzed Heterocycle Synthesis via C-H Activation, First Edition. Edited by Xiao-Feng Wu.

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“…31 Distortion/Interaction analysis of the Pd monomeric transition states indicates the origins of differences of activation energies in the ortho, meta and para transition states results from the differences of distortion energies of the template in the transition states. The meta and para transition states bearing 11-membered and 12-membered rings, outlined in color in Scheme 6, are highly distorted due to the ring strain.…”

Section: Palladium-silver Heterodimeric Model For Meta C–h Bond Acmentioning

confidence: 99%

Experimental–Computational Synergy for Selective Pd(II)-Catalyzed C–H Activation of Aryl and Alkyl Groups

et al. 2017

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CONSPECTUS C–H activation and functionalization are on the forefront of modern synthetic chemistry. Imagine if any C–H bond of a molecule could be converted to a C–X bond, where X is target functionality. Collaborations between many experimental and computational groups have led to rapid developments of new C–H functionalization methods. Our groups represent an example of this; we were brought together as part of the NSF-supported Center for Selective C–H Functionalization. Many examples of experimental-computational synergy for selective Pd(II)-catalyzed C–H activation of aryl and alkyl groups are described in this Account. We describe computations by the Houk group made in response to experimental stimuli by the Yu group. The first section discusses the experimental and computational investigations of oxazoline-directed, stereoselective Pd(II)-catalyzed C(sp3)–H bond activation that occurs through the concerted metalation-deprotonation (CMD) pathway involving a monomeric Pd functionality. The second section involves two types of bidentate ligands, mono-N-protected amino acid (MPAA) and acetyl-protected aminoethyl quinoline (APAQ) ligands that facilitate the C–H activation reactions in an internal base mechanism. In the MPAA-assisted remote C–H bond activation, the basic dianionic amidate ligand participates in the deprotonation of a specific C–H bond. This mechanism accounts for the improved reactivity and selectivity in C–H activation reactions with MPAA ligands. The chiral APAQ ligands enable the asymmetric palladium insertion into prochiral C–H bonds on a single methylene carbon center. The origins of the dramatic differences of 5-membered (relatively inactive) and 6-membered chelation (highly active) in the β-methylene C(sp3)–H activation reactions by Pd(II) catalyst were explained with density functional theory (DFT) calculations. This is mainly due to the steric repulsions between the ArF group of substrate and the quinoline group of the ligand. The steric repulsion between the ArF group of substrate and the quinoline group of the acetyl-protected aminomethyl quinoline ligand destabilizes the 5-membered chelate transition structure, increasing the energy of transition state. The third section discusses a mechanism involving a Pd-Ag heterodimeric complex intermediate in the template-directed, Pd(II)-catalyzed meta-functionalization of toluene derivatives and benzoic acid derivatives. The nitrile directing group of the template coordinates with Ag while the Pd is placed adjacent to the meta-C–H bond in the transition state, leading to the observed high meta-selectivity. The dual role of AgOAc as both an oxidant and part of the heteronuclear active species in the mechanism involving PdAg(OAc)3 was determined by DFT calculation. The interaction between the experimental and computational groups, and the interplay that led to these discoveries, are highlighted in this Account.

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Palladium-Catalyzed Meta-Selective C–H Bond Activation with a Nitrile-Containing Template: Computational Study on Mechanism and Origins of Selectivity

Cited by 342 publications

References 110 publications

Computational Studies of Synthetically Relevant Homogeneous Organometallic Catalysis Involving Ni, Pd, Ir, and Rh: An Overview of Commonly Employed DFT Methods and Mechanistic Insights

Computational Studies of Synthetically Relevant Homogeneous Organometallic Catalysis Involving Ni, Pd, Ir, and Rh: An Overview of Commonly Employed DFT Methods and Mechanistic Insights

Computational Studies of Heteroatom‐Assisted CH Activation at Ru, Rh, Ir, and Pd as a Basis for Heterocycle Synthesis and Derivatization

Experimental–Computational Synergy for Selective Pd(II)-Catalyzed C–H Activation of Aryl and Alkyl Groups

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