Aromaticity and Activation Strain Analysis of [3 + 2] Cycloaddition Reactions between Group 14 Heteroallenes and Triple Bonds

Fernández, Israel; Cossío, Fernando P.; Bickelhaupt, F. Matthias

doi:10.1021/jo102572x

Cited by 86 publications

(27 citation statements)

References 49 publications

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“…Interestingly, these results differ, for instance, from those of Fernández et al. on the [3+2] cycloaddition reactions between Group 14 heteroallenes and acetylene 11a. They found that the energy to deform the reactants to the transition‐state geometry represented the major factor in controlling the barrier heights; a difference probably associated with the already‐bent geometry of the fragment of [ 1 ] + that interacted with the alkyne in the present case.…”

Section: Resultscontrasting

confidence: 95%

Mechanism of [3+2] Cycloaddition of Alkynes to the [Mo₃S₄(acac)₃(py)₃][PF₆] Cluster

Pino-Chamorro

Gushchin

Fernández‐Trujillo

et al. 2014

Chemistry A European J

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A study, involving kinetic measurements on the stopped-flow and conventional UV/Vis timescales, ESI-MS, NMR spectroscopy and DFT calculations, has been carried out to understand the mechanism of the reaction of [Mo3 S4 (acac)3 (py)3 ][PF6 ] ([1]PF6 ; acac=acetylacetonate, py=pyridine) with two RCCR alkynes (R=CH2 OH (btd), COOH (adc)) in CH3 CN. Both reactions show polyphasic kinetics, but experimental and computational data indicate that alkyne activation occurs in a single kinetic step through a concerted mechanism similar to that of organic [3+2] cycloaddition reactions, in this case through the interaction with one Mo(μ-S)2 moiety of [1](+) . The rate of this step is three orders of magnitude faster for adc than that for btd, and the products initially formed evolve in subsequent steps into compounds that result from substitution of py ligands or from reorganization to give species with different structures. Activation strain analysis of the [3+2] cycloaddition step reveals that the deformation of the two reactants has a small contribution to the difference in the computed activation barriers, which is mainly associated with the change in the extent of their interaction at the transition-state structures. Subsequent frontier molecular orbital analysis shows that the carboxylic acid substituents on adc stabilize its HOMO and LUMO orbitals with respect to those on btd due to better electron-withdrawing properties. As a result, the frontier molecular orbitals of the cluster and alkyne become closer in energy; this allows a stronger interaction.

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Section: Resultscontrasting

confidence: 95%

Mechanism of [3+2] Cycloaddition of Alkynes to the [Mo₃S₄(acac)₃(py)₃][PF₆] Cluster

Pino-Chamorro

Gushchin

Fernández‐Trujillo

et al. 2014

Chemistry A European J

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“…However, it inverts at a certain point along the reaction coordinate and becomes more and more stabilized as one approaches the TS region. This behavior resembles that found not only for related cycloaddition reactions,, but also for other pericyclic reactions, such as double‐group transfer reactions, Alder–ene reactions, or ene–ene–yne cyclizations, and is different for other processes, such as S N 2 reactions, in which the Δ E int term is stabilizing along the entire reaction coordinate. Nevertheless, stabilization provided by the interaction term cannot compensate for the strong destabilizing effect of the deformation energy required to adopt the TS geometry (Δ E strain ), which, in turn, becomes the major factor that controls the activation barriers of the [4+2]‐cycloaddition reactions involving these geodesic polyarenes.…”

Section: Resultssupporting

confidence: 75%

Reactivity and Selectivity of Bowl‐Shaped Polycyclic Aromatic Hydrocarbons: Relationship to C₆₀

García-Rodeja

Solà

Bickelhaupt

et al. 2015

Chemistry A European J

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The Diels-Alder reactivity of different bowl-shaped polycyclic aromatic hydrocarbons (namely, corannulene, cyclopentacorannulene, diindenochrysene, hemifullerene, and circumtrindene) has been explored computationally within the Density Functional Theory framework. To this end, both the increase of the reactivity with the size of the buckybowl and the complete [6,6]-regioselectivity in the process have been analyzed in detail using the activation strain model of reactivity in combination with the energy decomposition analysis method. Our results have been compared to the parent C 60 fullerene, which also produces the corresponding [6,6]-cycloadduct exclusively. It is found that the behavior of the considered buckybowls resembles, in general, that of C 60 . Whereas the interaction energy between the deformed reactants along the reaction coordinate mainly controls the regioselectivity of the process, it is the interplay between the activation strain energy and the transition state interaction which governs the reactivity of the system.

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“…To get more information about the underlying interactions, we have additionally analyzed all (3 + 2) cycloadditions discussed above with the distortion/interaction or activation‐strain model . These models have successfully been applied to different pericyclic reactions , , . While the analysis for all transition states is given in the Supporting Information, Figure summarized the distortion/interaction analysis for four representative examples.…”

Section: Resultsmentioning

confidence: 99%

Regioselective 1,3‐Dipolar Cycloadditions of Diazoalkanes with Heteroatom‐Substituted Alkynes: Theory and Experiment

2018

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The 1,3‐dipolar cycloadditions of diazomethane and diazoethane with methyl 3‐(diethylamino)propiolate were investigated experimentally and computationally by employing density functional theory (DFT). The experiments provided methyl 3‐(diethylamino)‐pyrazole‐4‐carboxylates as the only isolated regioisomers. The constitution of these cycloadducts was secured by independent synthesis and decarboxylation to 3‐(diethylamino)pyrazoles. The calculations fully support the experimental findings. For the preferred pathway of the diazomethane cycloaddition with the alkyne, a kinetic preference of 9.6 kJ mol–1 was calculated in Et2O solution. The computational analysis was extended to other alkynes, for instance to heteroatom‐substituted alkynes such as ethoxyethyne and (ethylthio)ethyne. Again, the calculations nicely explain the switch in regioselectivity of the 1,3‐dipolar cycloadditions of diazomethane with these two alkynes, which has been reported earlier by the group of Arens.

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Aromaticity and Activation Strain Analysis of [3 + 2] Cycloaddition Reactions between Group 14 Heteroallenes and Triple Bonds

Cited by 86 publications

References 49 publications

Mechanism of [3+2] Cycloaddition of Alkynes to the [Mo₃S₄(acac)₃(py)₃][PF₆] Cluster

Mechanism of [3+2] Cycloaddition of Alkynes to the [Mo₃S₄(acac)₃(py)₃][PF₆] Cluster

Reactivity and Selectivity of Bowl‐Shaped Polycyclic Aromatic Hydrocarbons: Relationship to C₆₀

Regioselective 1,3‐Dipolar Cycloadditions of Diazoalkanes with Heteroatom‐Substituted Alkynes: Theory and Experiment

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Aromaticity and Activation Strain Analysis of [3 + 2] Cycloaddition Reactions between Group 14 Heteroallenes and Triple Bonds

Cited by 86 publications

References 49 publications

Mechanism of [3+2] Cycloaddition of Alkynes to the [Mo3S4(acac)3(py)3][PF6] Cluster

Mechanism of [3+2] Cycloaddition of Alkynes to the [Mo3S4(acac)3(py)3][PF6] Cluster

Reactivity and Selectivity of Bowl‐Shaped Polycyclic Aromatic Hydrocarbons: Relationship to C60

Regioselective 1,3‐Dipolar Cycloadditions of Diazoalkanes with Heteroatom‐Substituted Alkynes: Theory and Experiment

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Mechanism of [3+2] Cycloaddition of Alkynes to the [Mo₃S₄(acac)₃(py)₃][PF₆] Cluster

Mechanism of [3+2] Cycloaddition of Alkynes to the [Mo₃S₄(acac)₃(py)₃][PF₆] Cluster

Reactivity and Selectivity of Bowl‐Shaped Polycyclic Aromatic Hydrocarbons: Relationship to C₆₀