Unravelling the mechanism of cobalt (II) catalyzed O-arylation reaction between aryl halides and phenols: A DFT study

Rajalakshmi, C.; Radhakrishnan, Anjali; Sankuviruthiyil, M.Ujwaldev; Anilkumar, Gopinathan; Thomas, Vibin Ipe

doi:10.1016/j.jorganchem.2022.122385

Cited by 4 publications

(1 citation statement)

References 70 publications

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“…However, this SET pathway should be ruled out due to the highly unfavorable reaction free energy (Δ G = 43.0–44.4 kcal/mol) . On the other hand, the σ-bond metathesis pathway initiating with the addition of iodobenzene to 3 1 forms an intermediate 3 5B followed by the σ-bond metathesis transition state 3 TS 5B‑6B to generate the PhN(SiMe 3 ) 2 product along with the formation of an Co(I)-I species 3 6B (Scheme b). However, such a σ-bond metathesis process has to overcome a very high barrier of 53.4 kcal/mol and thus should be an unfavorable pathway for the C–I bond activation.…”

Section: Resultsmentioning

confidence: 99%

A Mechanistic Study of the Cobalt(I)-Catalyzed Amination of Aryl Halides: Effects of Metal and Ligand

et al. 2022

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Transition-metal-catalyzed amination of aryl halides is a useful approach for the synthesis of medicinal compounds, organic functional materials, and agrochemical compounds. A systematic DFT study has been performed to investigate the mechanism of the Co(I)-catalyzed amination of aryl halides by LiN(SiMe3)2 using (PPh3)3CoCl as the precatalyst. Our computational results suggest that the most favorable dissociative concerted C–I activation pathway in a triplet state consists of (a) dissociation of one PPh3 ligand, (b) concerted oxidative addition (OA) of the C–I bond, (c) transmetalation, (d) (optional) dissociation of the second PPh3 ligand, (e) C–N bond-forming reductive elimination (RE), and (f) ligand exchange to regenerate the active species. Comparatively, the associative concerted OA, radical, SH2/SN2, single electron transfer (SET), and σ-bond metathesis pathways should be less favorable due to their higher barriers or unfavorable reaction free energies. The effects of different metals (Rh and Ir) as centers in the catalyst were further examined and found to require higher reaction barriers, due to unfavorable dissociation of their stronger M–PPh3 bonds. These results highlight an advantage of the earth-abundant Co catalysts for the dissociative pathway(s). Overall, our study offers deeper mechanistic insights for the transition-metal-catalyzed amination and guides the design for efficient Co-based catalysts.

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Section: Resultsmentioning

confidence: 99%

A Mechanistic Study of the Cobalt(I)-Catalyzed Amination of Aryl Halides: Effects of Metal and Ligand

et al. 2022

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Unveiling the Novel Mechanistic Insights and Role of Base in Zn‐Catalyzed Csp–Csp² Cross‐Coupling Reaction

Rajalakshmi,

Krishnaveni,

Varghese

et al. 2024

J of Physical Organic Chem

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A detailed mechanistic investigation of the Zn (II)‐catalyzed Csp–Csp2 (Sonogashira‐type) cross‐coupling reaction is reported herein, using the Density Functional Theory method. The present study unveiled an unconventional non‐redox mechanism for Zn‐catalyzed cross‐coupling reaction, where the oxidation state of Zn remains intact throughout the catalytic cycle. Our study further revealed the significant role of the base in controlling the feasibility of cross‐coupling reactions that are catalyzed by electron‐deficient metal centers. Our study indicates that K3PO4 acts as an ancillary ligand (Lewis base) for the electron‐deficient Zn (II) catalytic center rather than as a proton abstractor for the nucleophilic coupling partner (phenylacetylene) in this reaction. The active catalyst was identified to be a four‐coordinate bis‐DMEDA Zn (II) complex. The mechanism proceeds via the initial activation of the nucleophilic coupling partner (phenylacetylene), followed by the electrophilic coupling partner (organic halide) activation liberating the cross‐coupled product by a concerted nucleophilic substitution pathway. The turn‐over limiting step was identified to be the activation of the electrophilic coupling partner. The activation barrier obtained for the reaction, 31.0 kcal/mol concords well with experimental temperature requirements (125°C). The coordination by base is found to stabilize the rate‐determining intermediates and transition states involved in the reaction. The mechanistic insights gained from this study could aid in the rational design and development of sustainable cross‐coupling reactions using zinc as the catalyst.

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Unveiling the molecular mechanism of Mn and Zn-catalyzed Ullmann-type C–O cross-coupling reactions

Rajalakshmi,

Santhoshkumar,

Mathews

et al. 2025

Phys. Chem. Chem. Phys.

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Unravelling the mechanism of cobalt (II) catalyzed O-arylation reaction between aryl halides and phenols: A DFT study

Cited by 4 publications

References 70 publications

A Mechanistic Study of the Cobalt(I)-Catalyzed Amination of Aryl Halides: Effects of Metal and Ligand

A Mechanistic Study of the Cobalt(I)-Catalyzed Amination of Aryl Halides: Effects of Metal and Ligand

Unveiling the Novel Mechanistic Insights and Role of Base in Zn‐Catalyzed Csp–Csp² Cross‐Coupling Reaction

Unveiling the molecular mechanism of Mn and Zn-catalyzed Ullmann-type C–O cross-coupling reactions

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Unravelling the mechanism of cobalt (II) catalyzed O-arylation reaction between aryl halides and phenols: A DFT study

Cited by 4 publications

References 70 publications

A Mechanistic Study of the Cobalt(I)-Catalyzed Amination of Aryl Halides: Effects of Metal and Ligand

A Mechanistic Study of the Cobalt(I)-Catalyzed Amination of Aryl Halides: Effects of Metal and Ligand

Unveiling the Novel Mechanistic Insights and Role of Base in Zn‐Catalyzed Csp–Csp2 Cross‐Coupling Reaction

Unveiling the molecular mechanism of Mn and Zn-catalyzed Ullmann-type C–O cross-coupling reactions

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Unveiling the Novel Mechanistic Insights and Role of Base in Zn‐Catalyzed Csp–Csp² Cross‐Coupling Reaction