In the searching for zwitterionic intermediates on reaction paths of [3 + 2] cycloaddition reactions between 2,2,4,4-tetramethyl-3-thiocyclobutanone S-methylide and polymerizable olefins

RSC Advances ◽  
2015 ◽  
Vol 5 (122) ◽  
pp. 101045-101048 ◽  
Author(s):  
Radomir Jasiński
Keyword(s):  
Dft Calculations ◽  
Cycloaddition Reactions ◽  
Reaction Paths ◽  
Zwitterionic Intermediate ◽  
Step Mechanism

DFT calculations show that the [3 + 2]-cycloaddition of 2,2,4,4-tetramethyl-3-thiocyclobutanone S-methylide with nitroethene takes place according to a polar, two-step mechanism with a zwitterionic intermediate.

scholarly journals On the Question of Zwitterionic Intermediates in the [3 + 2] Cycloaddition Reactions between C-arylnitrones and Perfluoro 2-Methylpent-2-ene

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7147
Author(s):  
Katarzyna Mitka ◽  
Katarzyna Fela ◽  
Aleksandra Olszewska ◽  
Radomir Jasiński
Keyword(s):  
Dft Calculations ◽  
Molecular Mechanism ◽  
Intermolecular Interactions ◽  
Cycloaddition Reaction ◽  
Reaction Centers ◽  
Cycloaddition Reactions ◽  
Reaction Paths ◽  
One Step ◽  
Step Mechanism

The molecular mechanism of the [3 + 2] cycloaddition reaction between C-arylnitrones and perfluoro 2-methylpent-2-ene was explored on the basis of DFT calculations. It was found that despite the polar nature of the intermolecular interactions, as well as the presence of fluorine atoms near the reaction centers, all reactions considered cycloaddition proceed via a one-step mechanism. All attempts for the localization of zwitterionic intermediates on the reaction paths were not successful. Similar results were obtained regardless of the level of theory applied.

scholarly journals Application of β-Phosphorylated Nitroethenes in [3+2] Cycloaddition Reactions Involving Benzonitrile N-Oxide in the Light of a DFT Computational Study

Organics ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 26-37
Author(s):  
Karolina Zawadzińska ◽  
Karolina Kula
Keyword(s):  
Density Functional ◽  
Reaction Path ◽  
Computational Study ◽  
Cyano Group ◽  
Cycloaddition Reactions ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Reaction Channels ◽  
One Step ◽  
Step Mechanism

The regiochemistry of [3+2] cycloaddition (32CA) processes between benzonitrile N-oxide 1 and β-phosphorylated analogues of nitroethenes 2a–c has been studied using the Density Functional Theory (DFT) at the M062X/6-31+G(d) theory level. The obtained results of reactivity indices show that benzonitrile N-oxide 1 can be classified both as a moderate electrophile and moderate nucleophile, while β-phosphorylated analogues of nitroethenes 2a–c can be classified as strong electrophiles and marginal nucleophiles. Moreover, the analysis of CDFT shows that for [3+2] cycloadditions with the participation of β-phosphorylatednitroethene 2a and β-phosphorylated α-cyanonitroethene 2b, the more favored reaction path forms 4-nitro-substituted Δ2-isoxazolines 3a–b, while for a reaction with β-phosphorylated β-cyanonitroethene 2c, the more favored path forms 5-nitro-substituted Δ2-isoxazoline 4c. This is due to the presence of a cyano group in the alkene. The CDFT study correlates well with the analysis of the kinetic description of the considered reaction channels. Moreover, DFT calculations have proven the clearly polar nature of all analyzed [3+2] cycloaddition reactions according to the polar one-step mechanism.

scholarly journals Unraveling reaction networks behind the catalytic oxidation of methane with H2O2 over a mixed-metal MIL-53(Al,Fe) MOF catalyst

2018 ◽  
Vol 9 (33) ◽  
pp. 6765-6773 ◽  
Author(s):  
Ágnes Szécsényi ◽  
Guanna Li ◽  
Jorge Gascon ◽  
Evgeny A. Pidko
Keyword(s):  
Dft Calculations ◽  
Catalytic Oxidation ◽  
Metal Organic Framework ◽  
Reaction Networks ◽  
Reaction Paths ◽  
Mixed Metal ◽  
Oxidation Of Methane ◽  
Metal Organic ◽  
Periodic Dft Calculations ◽  
Periodic Dft

Reaction paths underlying the catalytic oxidation of methane with H2O2 over an Fe containing MIL-53(Al) metal–organic framework were studied by periodic DFT calculations.

scholarly journals Study of Kinetics, Equilibrium and the Influence of Steric Effects on Proton-Transfer in the Reactions of 2, 2, 4- and 2, 6- Substituted Anilines with 2-Phenoxy-3,5-dinitropyridine in DMSO

2010 ◽  
Vol 7 (1) ◽  
pp. 253-259 ◽  
Author(s):  
Basim H. Asghar
Keyword(s):  
Proton Transfer ◽  
Steric Effect ◽  
Nucleophilic Attack ◽  
Steric Effects ◽  
Substituted Anilines ◽  
Phenoxy Group ◽  
Kinetics Studies ◽  
Zwitterionic Intermediate ◽  
Rate Limiting ◽  
Step Mechanism

Kinetic and equilibrium results for the reactions of 2-phenoxy-3,5-dinitropyridine (1), with a series of 2, 2, 4- and 2, 6- substituted anilines (2a-f), in the presence of DABCO in DMSO are reported. The reactions yield the 2-anilino derivatives (5), without the accumulation of intermediates. Kinetics studies are compatible with a two-step mechanism involving initial nucleophilic attack by amine at the ring carbon substituted by phenoxy group followed by either base-catalyzed or uncatalyzed conversion to the product. The base-catalyzed pathway is likely to involve rate-limiting proton-transfer from the zwitterionic intermediate to base. This work indicates a steric effect to proton transfer in reactions involving 2, 6-disubstituted anilines. The results were compared with those for reactions of 1, 3, 5-trinitrobenzene with anilines.

A first principles study of H2S adsorption and decomposition on a Ge(100) surface

RSC Advances ◽  
2015 ◽  
Vol 5 (5) ◽  
pp. 3825-3832 ◽  
Author(s):  
Tsung-Fan Teng ◽  
Santhanamoorthi Nachimuthu ◽  
Wei-Hsiu Hung ◽  
Jyh-Chiang Jiang
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
First Principles ◽  
Density Functional ◽  
Reaction Paths ◽  
Functional Theory ◽  
First Principles Study ◽  
H2s Adsorption

We employed density functional theory (DFT) calculations to examine the adsorption configurations and possible reaction paths for H2S on a Ge(100) surface.

Mechanism and regioselectivity of 1,3-dipolar cycloaddition reactions of bicyclic monoterpenes with aryl and heteroaryl nitrile oxides: a DFT study

2015 ◽  
Vol 93 (7) ◽  
pp. 749-753 ◽  
Author(s):  
Hossein Eshghi ◽  
Amir Khojastehnezhad ◽  
Farid Moeinpour ◽  
Mehdi Bakavoli
Keyword(s):  
Gas Phase ◽  
Density Functional ◽  
Energy Surface ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Functional Theory ◽  
Nitrile Oxides ◽  
Reactivity Indices ◽  
One Step ◽  
Step Mechanism

The reactivity and regioselectivity of 1,3-dipolar cycloaddition reactions of aryl and heteroaryl nitrile oxides (1a–1c) with bicyclic monoterpenes (R)-(+)-a-pinene (2a) and (S)-(–)-b-pinene (2b) have been investigated by using density functional theory based on reactivity indices and activation energy calculations at the B3LYP/6-31G(d) level of theory in the gas phase. The potential energy surface analyses for both reactions are in agreement with the experimental observations. Moreover, our calculations on the geometries, bond orders, and global electron density transfers at the transition state structures shows that these 1,3- dipolar cycloaddition reactions occur via an asynchronous one-step mechanism.

Nitrones and oxaziridines. XXI. Electronic substituent effects in nitrone cycloadditions to highly polarized alkenes

1978 ◽  
Vol 31 (10) ◽  
pp. 2239 ◽  
Author(s):  
DSC Black ◽  
RF Crozier ◽  
ID Rae
Keyword(s):  
Substituent Effects ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Zwitterionic Intermediate

1,3-Dipolar cycloaddition reactions of nitrones-particularly N-(2'- pyridylmethylene)aniline N-oxide-with arylmethylene cyanoacetates exclusively yield 4,4-disubstituted isoxazolidines, identifiable by 1H n.m.r, spectroscopy and isolable in some cases. Comparative kinetic experiments provide evidence for at least non-synchronous addition via a dipolar intermediate or possibly even two-step addition via a discrete zwitterionic intermediate.

Inter- and Intramolecular Cycloaddition Reactions of Ethenetricarboxylates with Styrenes and Halostyrenes

Synthesis ◽  
2020 ◽  
Author(s):  
Shoko Yamazaki ◽  
Zhichao Wang ◽  
Kentaro Iwata ◽  
Khotaro Katayama ◽  
Hirotaka Sugiura ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Reaction Mechanisms ◽  
Cycloaddition Reactions ◽  
Intramolecular Cycloaddition ◽  
High Diversity

AbstractInter- and intramolecular cycloaddition reactions of ethenetricarboxylates with styrenes and α-halostyrenes have been investigated. The reactions of ethenetricarboxylates with styrenes or α-bromostyrenes in the presence of SnCl4 or SnBr4 stereoselectively gave 2,4-cis-substituted cyclobutanes. The intramolecular cycloaddition reactions of a series of styrene-functionalized ethenetricarboxylate amides, including in situ generated derivatives, showed high diversity of reaction modes depending on the structures and substituents of the substrates. The regioselectivity and stereoselectivity of the reactions as well as reaction mechanisms were discussed based on the DFT calculations.

scholarly journals Regio- and Stereoselectivity in the 1,3-Dipolar Cycloaddition Reactions of Isoquinolinium Ylides with Cyclopenta[a]acenaphthylen-8-ones

Synlett ◽  
2020 ◽  
Vol 31 (17) ◽  
pp. 1691-1695
Author(s):  
Issa Yavari ◽  
Parisa Ravaghi ◽  
Maryam Safaei ◽  
Jasmine Kayanian
Keyword(s):  
Dft Calculations ◽  
Cycloaddition Reaction ◽  
Crystallographic Analysis ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Diastereoselective Synthesis ◽  
X Ray

AbstractA convenient regio- and diastereoselective synthesis of functionalized 5a,5b-dihydro-5H,13H-naphtho[1′′,8′′:4′,5′,6′]pentaleno[1′:3,4]pyrrolo[2,1-a]isoquinolin-5-ones via 1,3-dipolar cycloaddition reaction of 8H-cyclopenta[a]acenaphthylen-8-ones with carbonyl-stabilized isoquinolinium N-ylides, is described. Based on DFT calculations at b3lyp/6-311+g(d,p) level of theory, a nonconcerted mechanism is proposed to explain the regioselectivity of this reaction. The structure of a typical product was confirmed by X-ray crystallographic analysis.

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