DFT studies on the mechanisms of enantioselective Ni-catalyzed reductive coupling reactions to form 1,1-diarylalkanes

Ren, Qinghua; Zhang, Dongtao; Zheng, Lin

doi:10.1016/j.jorganchem.2021.122042

Cited by 6 publications

(4 citation statements)

References 59 publications

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“…19,103,122,[151][152][153][154] Ligand effects have always been a research hotspot in transition metal-catalyzed coupling reactions. [155][156][157] The group of Rueping and Cavallo reported an example of ligand-controlled chemoselective C(acyl)-O bond vs. C(aryl)-C bond activation of aromatic esters. 158 The computational results suggested that nickel complexes with monodentate phosphorus ligands (P n Bu 3 ) favored the activation of the C(acyl)-O bond via TS33 with an activation energy of 22.7 kcal mol À1 , whereas nickel complexes with bidentate ligands (type) favored the cleavage of C(aryl)-C bond in the oxidative addition step via TS36 with a barrier of 28.1 kcal mol À1 (Fig.…”

Section: Origin Of Selectivity For the Activation Of Electrophilesmentioning

confidence: 99%

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Mechanistic views and computational studies on transition-metal-catalyzed reductive coupling reactions

et al. 2022

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Section: Origin Of Selectivity For the Activation Of Electrophilesmentioning

confidence: 99%

“…19,103,122,151–154 Ligand effects have always been a research hotspot in transition metal-catalyzed coupling reactions. 155–157…”

Section: Mechanism Of Electrophile Activationmentioning

confidence: 99%

Mechanistic views and computational studies on transition-metal-catalyzed reductive coupling reactions

et al. 2022

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“…The cross-coupling reactions using the transition-metal catalysts are broadly used in the formation of organic molecule for several decades . Many transition-metals have been used which reaction types are increasingly diversified, such as, palladium, nickel, iridium, ruthenium, rhodium, gold, and so forth. However, these precious metals are normally limited by the toxicity, high price, sustainability, and other disadvantages.…”

Section: Introductionmentioning

confidence: 99%

DFT Study on the Mechanisms of Iron-Catalyzed Ortho C–H Homoallylation of Aromatic Ketones with Methylenecyclopropanes

2023

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The mechanisms of iron-catalyzed ortho C–H homoallylation of aromatic ketones with methylenecyclopropanes are calculated using density functional theory calculations with B3LYP-D3BJ functionals and solvation model density (cyclohexane) model. Our results show that the catalytic cycle includes C–H bond oxidative addition, insertion of C–C double bond, ring-opening reaction, reductive elimination, ligand exchange, and the catalyst regeneration. Two possible catalytic cycles are calculated, where Path A is where the iron active catalyst first combined with 2,2-dimethyl-1-[4-(trifluoromethyl) phenyl]-propan-1-one and Path B is where the iron active catalyst initially attacked 2-phenyl-1-methylenecyclopropane. Our calculated results show that the rate-determining step in the whole catalytic cycle for the favored Path A is the C–H bond oxidation addition step, where Gibbs free energy in solvent cyclohexane, ΔG sol, is 10.8 kcal/mol.

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“…A equação (76) subtraída da equação (77) resulta em uma expressão para energia de interação eletrônica do sistema físico. O somatório dessas equações foram organizados para facilitar a identificação das integrais de dois elétrons (𝐺 𝜇𝑣 , ver equação 67).…”

Section: 𝑭𝑪 = 𝑺𝑪𝝐unclassified

Estudo computacional do mecanismo de acoplamento cruzado C-C via dupla ativação das ligações C-O de éteres catalisado por complexo de níquel

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C−O activation is an excellent strategy to promote cross-coupling reactions of oxygenated electrophiles 1 . A new methodology for ether deoxygenation catalyzed by Ni(dppb), in the presence of zinc dust and B 2 pin 2 as likely reducing agent and oxygen acceptor, respectively, was developed by Shi and Cao 1 . The relevance of this methodology lies on the fact that both C−O bonds are activated, resulting in the union of both ether carbon chains, granting a good atom economy to the system. Thereby, in this study, the molecular mechanism of the ether deoxygenation reaction was characterized, via electronic structure calculations. The calculations were performed in DFT/PBE-D3 level. Several mechanistic pathways were considered in the present work and it was concluded that in the absence of bis(pinacolato) diboron in the reaction medium, the kinetically favored cycle occurs through the steps of i) 1st oxidative addition, which is associated with the breaking of an ether C-O bond with concomitant connection of its fragments to the nickel of the catalyst; ii) reduction of the Ni(II) complex generated to Ni(I), via abstraction of its alkoxide group by metallic zinc; iii) formation of an alkyl radical through the reaction of the Ni(I) intermediate with a new ether molecule, again, only one of the substrate C-O bonds is cleaved; iv) further reduction of the nickel complex to Ni(I); v) addition of the radical formed in step (iii) to the Ni(I) complex and v) reductive elimination, which leads to C-C coupling between the carbon fragments of the two consumed ethers. The formation of the alkyl radical was identified as the ratedetermining event of this catalytic cycle with ∆G ‡ = 31.0 kcal/mol. When B 2 pin 2 is present in the reaction medium, it reacts with an alkoxide group anchored to the zinc surface and not used in the previously discussed cycle. This reaction promotes the breakage of the 2nd C-O bond of the ether and forms an alkyl radical consisting of its entire carbonic fragment that binds to the Ni(I) complex, and the most energetic barrier is associated with the desorption of the radical from the metallic surface, followed by its connection to the nickel complex with ∆G ‡ = 31.5 kcal/mol. As the barriers differ by only 0.5 kcal/mol, it is concluded that both cycles are equally competitive and that (bis)pinacolato diboron increases the experimental yield significantly, as it transforms the reactional stoichiometry from 2R→1P to 1R→1P.

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DFT studies on the mechanisms of enantioselective Ni-catalyzed reductive coupling reactions to form 1,1-diarylalkanes

Cited by 6 publications

References 59 publications

Mechanistic views and computational studies on transition-metal-catalyzed reductive coupling reactions

Mechanistic views and computational studies on transition-metal-catalyzed reductive coupling reactions

DFT Study on the Mechanisms of Iron-Catalyzed Ortho C–H Homoallylation of Aromatic Ketones with Methylenecyclopropanes

Estudo computacional do mecanismo de acoplamento cruzado C-C via dupla ativação das ligações C-O de éteres catalisado por complexo de níquel

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