Nitropyrroles, Diels-Alder reactions assisted by microwave irradiation and solvent effect. An experimental and theoretical study

Mancini, Paolo; Kneeteman, Marı́a N.; Cainelli, Mauro; Ormachea, Carla; Domingo, Luís R.

doi:10.1016/j.molstruc.2017.06.109

Cited by 13 publications

(8 citation statements)

References 32 publications

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“…Besides, they provide rather good saddle point geometries. On the top of that, weak interactions of special importance for Diels–Alder reactions 16–19 are well described. The nature of the stationary points was confirmed by frequency calculations, in which the transition states possess only one imaginary frequency corresponding to the new forming bonds.…”

Section: Theoretical Methodsmentioning

confidence: 99%

A computational investigation of the selectivity and mechanism of the Lewis acid catalyzed oxa‐Diels–Alder cycloaddition of substituted diene with benzaldehyde

et al. 2021

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The selectivity and the mechanism of the uncatalyzed and AlCl3 catalyzed hetero‐Diels–Alder reaction (HDR) between ([E]‐4‐methylpenta‐2,4‐dienyloxy)(tert‐butyl)dimethylsilane 1 and benzaldehyde 2 have been studied using density functional theory at the MPWB1K/6‐31G(d) level of theory. The uncatalyzed HDR between diene 1 and alkene 2 is characterized by a polar character and proceeds via an asynchronous one‐step mechanism for the meta paths and synchronous for the ortho ones. In the presence of AlCl3 catalyst, the mechanism changes to be stepwise, while the first step is the rate‐determining step. The activation energies widely decrease, and the polar character increases dramatically. A large analysis of the mechanism is performed using the activation strain model/energy decomposition analysis (ASM/EDA) model, the natural bond orbital (NBO) and state specific dual descriptors (SSDDs). The obtained results indicate that the combined interaction energy associated with the distortion of the reactants in these HDR are at the origin of the observed kinetics. NBO analyses were applied to estimate the Lewis‐acid catalyst donor‐acceptor interaction with the molecular system. The SSDD analysis shed light into the orientation effects on the reaction kinetics by providing important information about charge transfer interactions during the chemical reaction. It indicates that the more favorable HDR pathway have the lowest excitation energies, facilitating the interaction between diene 1 and benzaldehyde 2 moieties. Non‐covalent interaction (NCI) and QTAIM analyses of the meta‐endo structure indicate that the presence of several weak NCIs formed at this approach is at the origin of the meta‐endo selectivity.

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Section: Theoretical Methodsmentioning

confidence: 99%

A computational investigation of the selectivity and mechanism of the Lewis acid catalyzed oxa‐Diels–Alder cycloaddition of substituted diene with benzaldehyde

et al. 2021

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“…When a higher alcohol, i.e., octanol, was used in the solvent mixture, the low-polarity solvent did not absorb microwaves to a considerable extent [7].…”

Section: Effect Of Microwave Irradiation On Ferrocene Nucleusmentioning

confidence: 99%

“…In addition, selective absorption of microwaves by protic solvents, polar substrates, and polar reaction intermediates is considered to be a major factor contributing to the increased reaction rates under microwave irradiation [7].…”

Section: Introductionmentioning

confidence: 99%

Effect of Microwave Irradiation on Oximation of Acetylferrocene

Okada¹,

Maeda²

2021

GSC

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Microwave-assisted reactions are an environmentally friendly approach for synthesizing organic compounds. In this study, oximation of acetylferrocene and acetophenone was conducted under both microwave irradiation and conventional heating conditions. Acetylferrocene and acetophenone were subjected to oximation under the two conditions in various solvent mixtures, and the extent of conversion was determined by 1 H nuclear magnetic resonance spectroscopy. Microwave irradiation was found to accelerate the rate of oximation of both acetylferrocene and acetophenone. Acceleration of the reaction under microwave irradiation was attributed to the efficient absorption of microwaves by the ferrocene nucleus.

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“…Thus, theoretical studies by density functional theory (DFT) are used to analyze the reactivity of these compounds. The advancement of the conceptual DFT method brought about by modern density functional theory will justify several visions about varied chemical transformations 24–28 . Reactions included isopolar activated complexes like the Diels‐Alder reaction that usually show small solvent effects; thus, studies on this subject have usually been infrequent.…”

Section: Introductionmentioning

confidence: 99%

Computational investigation of the substituent effect in the [2 + 4] Diels–Alder cycloaddition reactions of HSi≡Si(para‐C₆H₄X) with benzene

Ahraminejad

Ghiasi

Mohtat

et al. 2021

J Chinese Chemical Soc

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In this paper, the DFT method was applied at the B3LYP/6-311+G (d,p) level of theory to investigate the [2 + 4] Diels−Alder cycloaddition reactions of HSi≡Si(para-C 6 H 4 X); X = NH 2 , OH, Me, H, F, CCH, OCF 3 with benzene. It was attempted to show how the substituent affects the barrier height and thermodynamic parameters of these reactions. To illustrate the interaction between two fragments at transition states Activation Strain Model (ASM) and Energy Decomposition Analysis (EDA) were utilized. The Wiberg bond indices were used to check the progress of the reactions. The rate constant of the reaction was computed at 300 K, in the gas phase. Also, the synchronicity values of this reaction were determined. K E Y W O R D S rhenabenzyne, phosphine ligand, natural bond analysis (NBO), Tolman cone angles, Tolman's electronic parameter (TEP), para-delocalization index (PDI)

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Nitropyrroles, Diels-Alder reactions assisted by microwave irradiation and solvent effect. An experimental and theoretical study

Cited by 13 publications

References 32 publications

A computational investigation of the selectivity and mechanism of the Lewis acid catalyzed oxa‐Diels–Alder cycloaddition of substituted diene with benzaldehyde

A computational investigation of the selectivity and mechanism of the Lewis acid catalyzed oxa‐Diels–Alder cycloaddition of substituted diene with benzaldehyde

Effect of Microwave Irradiation on Oximation of Acetylferrocene

Computational investigation of the substituent effect in the [2 + 4] Diels–Alder cycloaddition reactions of HSi≡Si(para‐C₆H₄X) with benzene

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Nitropyrroles, Diels-Alder reactions assisted by microwave irradiation and solvent effect. An experimental and theoretical study

Cited by 13 publications

References 32 publications

A computational investigation of the selectivity and mechanism of the Lewis acid catalyzed oxa‐Diels–Alder cycloaddition of substituted diene with benzaldehyde

A computational investigation of the selectivity and mechanism of the Lewis acid catalyzed oxa‐Diels–Alder cycloaddition of substituted diene with benzaldehyde

Effect of Microwave Irradiation on Oximation of Acetylferrocene

Computational investigation of the substituent effect in the [2 + 4] Diels–Alder cycloaddition reactions of HSi≡Si(para‐C6H4X) with benzene

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Computational investigation of the substituent effect in the [2 + 4] Diels–Alder cycloaddition reactions of HSi≡Si(para‐C₆H₄X) with benzene