A detailed analysis of the mechanism of a carbocationic triple shift rearrangement

Ortega, Daniela E.; Gutiérrez‐Oliva, Soledad; Tantillo, Dean J.; Toro–Labbé, Alejandro

doi:10.1039/c4cp03819c

Cited by 26 publications

(19 citation statements)

References 34 publications

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“…Thus, by using Equation (8) at each point along ξ it is possible to obtain a chemical potential profile μ ( ξ ). Now, to analyze the electronic activity taking place along a reaction coordinate, the reaction electronic flux (REF) has been introduced; it is defined in Equation .

true J (ξ) = - \frac{normald μ (ξ)}{normald ξ}

…”

Section: Theorymentioning

confidence: 99%

“…Positive values of J ( ξ ) indicate spontaneous changes in the electronic density, changes that are driven by bond‐forming or bond‐strengthening processes. On the other hand, negative values of J ( ξ ) are evidence of non‐spontaneous electronic activity, this is driven by bond‐weakening or bond‐breaking processes …”

Section: Theorymentioning

confidence: 99%

“…On the other hand, negative values of J(x)a re evidenceo fn onspontaneous electronic activity,t his is driven by bond-weakening or bond-breaking processes. [25,34,[46][47][48][49][50]…”

Section: Jðxþ¼à Dmðxþ DX ð9þmentioning

confidence: 99%

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Double Gold Activation of 1‐Ethynyl‐2‐(Phenylethynyl)Benzene Toward 5‐exo‐dig and 6‐endo‐dig Cyclization Reactions

Villegas‐Escobar

Vilhelmsen

Gutiérrez‐Oliva

et al. 2017

Chemistry A European J

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In this work, a detailed characterization was carried out of the ring-closure mechanism of EPB (1-ethynyl-2-(phenylethynyl)benzene) toward the 5-exo-dig and 6-endo-dig cyclization reactions, catalyzed by two Au-N-heterocyclic carbene (NHC) moieties. It was found that the 5-exo-dig cyclization takes place with a slightly lower activation barrier and larger exothermicity compared to that of the 6-endo-dig cyclization, in agreement with the available experimental data. A phenomenological partition (structural and electronic) for rate constants computed using transition-state theory and the reaction force analysis was used to shed light into the nature of the activation rate constant. It was found that rate constants are influenced by a strong structural component, which is larger for the 5-exo-dig cyclization due to the strain to form the five-membered ring. On the other hand, the gold activation mechanism is evidenced by a σ- and π-coordination of the Au-NHC moieties to the EPB substrate. It was found that differences in the σ-coordination arise on the reaction path for the 5-exo-dig and 6-endo-dig cyclizations. Thus, in the 6-endo-dig cyclization the σ gold-EPB interaction is weakened as a consequence of the formation of the cationic aryl intermediate, while for the 5-exo-dig cyclization this interaction was found to be favored. Furthermore, although minor changes in the Au-EPB coordination occur on the reaction path, these bonds are formally established in the TS vicinity. Results support the concerted nature of the dual gold activation mechanism.

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true J (ξ) = - \frac{normald μ (ξ)}{normald ξ}

…”

Section: Theorymentioning

confidence: 99%

Section: Theorymentioning

confidence: 99%

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Double Gold Activation of 1‐Ethynyl‐2‐(Phenylethynyl)Benzene Toward 5‐exo‐dig and 6‐endo‐dig Cyclization Reactions

Villegas‐Escobar

Vilhelmsen

Gutiérrez‐Oliva

et al. 2017

Chemistry A European J

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“…The reader is referred to the appropriate references to review the original formulation of the RF concept. Here, it is directly indicated that, from the IRC results, the RF can be readily defined as follows:

italicF ((), ξ) = - \frac{dE}{italicd ξ}

…”

Section: Computational Methodlogymentioning

confidence: 99%

Theoretical study of the furfuryl benzoate and furfuryl acetate pyrolysis

Mora

Rincón

Torres

et al. 2017

J of Physical Organic Chem

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In the present work, the pyrolysis reaction mechanism of both furfuryl benzoate and furfuryl acetate was evaluated at the M06/6‐311++g(d,p) level. The uncommon methylenecyclobutenone compound and either the benzoic or the acetic acid were determined as the products of a multistep process consisting in two [3 + 3] rearrangements and a subsequent hydrogen α‐elimination step, through a cyclic 5‐membered transition state (TS), being the latter the rate‐limiting step for both reactants. Furthermore, a deeper analysis on the basis of the reaction force formalism showed that the TS is formed in two stages: The first one is characterized by the weakening of the C─O bond, and the second one is where the H atom is transferred from the C atom to its nearest O atom. The H─O bond formation was determined to contribute the most to the electronic activity occurring during the TS formation as suggested by a reaction electronic flux analysis. Accordingly, natural bond orbital calculations showed that the most significant changes occur in the charge distribution of the O and H atoms. Finally, a negligible effect of the substituting group on the reaction was determined since similar activation energies were obtained for the pyrolysis of furfuryl benzoate and furfuryl acetate; however, a minor difference was evidenced in the reaction force results. In this sense, the structural contribution to the activation energy is larger than the electronic one for the furfuryl benzoate reaction, w1SR>w2SR, whereas the opposite is observed for the furfuryl acetate reaction, w1SR>w2SR.

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“…F n ð Þ profile has a minimum and a maximum at the inflection points of E n ð Þ and through this different regions along the reaction coordinate can be defined. [10,11] For an one-step reaction F n ð Þ presents two critical points n 1 ; n 2 f g; the first one localized between the reactants and the transition state; the second one is localized between the transition state and the products. Three reaction regions are defined: the reactant region n R n n 1 ð Þ that involves preparation of reactants to chemical transformation and is dominated by structural rearrangements (bond lengthening, rotation, angle changes, etc.…”

Section: Theoretical Frameworkmentioning

confidence: 99%

The catalytic effect of the NH₃ base on the chemical events in the caryolene‐forming carbocation cascade

et al. 2016

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Caryolene formation occur asynchronously in a concerted way through carbocationic rearrangements involving the generation of a secondary or a tertiary carbocation whether the reaction proceeds in the absence or in the presence of NH3 , respectively. Both caryolene formation mechanisms are analyzed within the general framework of the reaction force; the reaction force constant is used to gain insights into the synchronicity of the mechanisms and the reaction electronic flux helps to characterize the electronic activity taking place during the reaction. DFT calculations at the B3LYP/6-31+G(d,p) level show a clear difference in the mechanisms of the base promoted or base free caryolene formation reactions.

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A detailed analysis of the mechanism of a carbocationic triple shift rearrangement

Cited by 26 publications

References 34 publications

Double Gold Activation of 1‐Ethynyl‐2‐(Phenylethynyl)Benzene Toward 5‐exo‐dig and 6‐endo‐dig Cyclization Reactions

Double Gold Activation of 1‐Ethynyl‐2‐(Phenylethynyl)Benzene Toward 5‐exo‐dig and 6‐endo‐dig Cyclization Reactions

Theoretical study of the furfuryl benzoate and furfuryl acetate pyrolysis

The catalytic effect of the NH₃ base on the chemical events in the caryolene‐forming carbocation cascade

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A detailed analysis of the mechanism of a carbocationic triple shift rearrangement

Cited by 26 publications

References 34 publications

Double Gold Activation of 1‐Ethynyl‐2‐(Phenylethynyl)Benzene Toward 5‐exo‐dig and 6‐endo‐dig Cyclization Reactions

Double Gold Activation of 1‐Ethynyl‐2‐(Phenylethynyl)Benzene Toward 5‐exo‐dig and 6‐endo‐dig Cyclization Reactions

Theoretical study of the furfuryl benzoate and furfuryl acetate pyrolysis

The catalytic effect of the NH3 base on the chemical events in the caryolene‐forming carbocation cascade

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Product

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The catalytic effect of the NH₃ base on the chemical events in the caryolene‐forming carbocation cascade