A molecular electron density theory study on the [3+2] cycloaddition reaction of thiocarbonyl ylides with hetaryl thioketones

2018 ◽  
Vol 42 (14) ◽  
pp. 11819-11830 ◽  
Author(s):  
Afsaneh Asr ◽  
Mehran Aghaie ◽  
Saeedreza Emamian ◽  
Hossein Aghaie
Keyword(s):  
Molecular Mechanism ◽  
Electron Density ◽  
Cycloaddition Reaction ◽  
Two Stage ◽  
Molecular Electron ◽  
One Step ◽  
Molecular Electron Density Theory

In situ generated TCY 2 is trapped with THK 3 over the course of a non-polar, entirely C1–C4 regioselective, pdr-type 32CA reaction passing through TS 1 in a non-concerted two-stage one-step molecular mechanism.

scholarly journals A molecular electron density theory study of the [3 + 2] cycloaddition reaction of nitrones with ketenes

2017 ◽  
Vol 15 (7) ◽  
pp. 1618-1627 ◽  
Author(s):  
Mar Ríos-Gutiérrez ◽  
Andrea Darù ◽  
Tomás Tejero ◽  
Luis R. Domingo ◽  
Pedro Merino
Keyword(s):  
Electron Density ◽  
Cycloaddition Reaction ◽  
Molecular Electron ◽  
One Step ◽  
Molecular Electron Density Theory ◽  
Electrophilic Character

The zw-type 32CA reactions of nitrones with ketenes are controlled by the nucleophilic character of the nitrone and the electrophilic character of the ketene. They are chemo- and regio-selective and the use of electrophilic ketenes changes the mechanism from one-step to two-step.

scholarly journals Mpro-SARS-CoV-2 Inhibitors and Various Chemical Reactivity of 1-Bromo- and 1-Chloro-4-vinylbenzene in [3 + 2] Cycloaddition Reactions

Organics ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 1-16
Author(s):  
Mohammed El Idrissi ◽  
Mohamed El Ghozlani ◽  
Asli Eşme ◽  
Mar Ríos-Gutiérrez ◽  
Anas Ouled Aitouna ◽  
...  
Keyword(s):  
Electron Density ◽  
Chemical Reactivity ◽  
Cycloaddition Reactions ◽  
Two Stage ◽  
Docking Analysis ◽  
Molecular Electron ◽  
One Step ◽  
Molecular Electron Density Theory ◽  
Step Mechanism ◽  
Computational Level

The regioselectvity and the mechanism of the (32CA) cycloadditions reactions of 1-bromo-4-vinylbenzene 1 and 1-chloro-4-vinylbenzene 2 with benzonitrile oxide 3 were investigated under the molecular electron density theory (MEDT) at the B3LYP/6-311++G(d,p) computational level. Evaluation of the ELF reveals that these zwitterionic type (zw-type) 32CA reactions take place in a two-stage one-step mechanism. This MEDT study shows that the meta isoxazolines are kinetically and thermodynamically favored over the ortho ones, these 32CA reactions being completely regioselective, in agreement with experimental outcomes. In addition, the efficiency of isoxazolines against SARS-CoV-2 have been also investigated. According to the docking analysis, the present study concludes that 5-(p-bromophenyl)-3-phenyl-2-isoxazoline (B-m) shows better interactions for the inhibition of SARS-CoV-2 in comparison to chloroquine.

scholarly journals The Participation of 3,3,3-Trichloro-1-Nitroprop-1-Ene in the [3 + 2] Cycloaddition Reaction with Selected Nitrile N-oxides in the Light of the Experimental and MEDT Quantum Chemical Study

Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 6774
Author(s):  
Karolina Zawadzińska ◽  
Mar Ríos-Gutiérrez ◽  
Karolina Kula ◽  
Przemysław Woliński ◽  
Barbara Mirosław ◽  
...  
Keyword(s):  
Electron Density ◽  
Quantum Chemical Study ◽  
Cycloaddition Reaction ◽  
Chemical Study ◽  
Free Energies ◽  
Molecular Electron ◽  
One Step ◽  
Molecular Electron Density Theory ◽  
Favorable Reaction ◽  
Type 3

The regioselective zw-type [3 + 2] cycloaddition (32CA) reactions of a series of aryl-substituted nitrile N-oxides (NOs) with trichloronitropropene (TNP) have been both experimentally and theoretically studied within the Molecular Electron Density Theory (MEDT). Zwitterionic NOs behave as moderate nucleophiles while TNP acts as a very strong electrophile in these polar 32CA reactions of forward electron density flux, which present moderate activation Gibbs free energies of 22.8–25.6 kcal·mol−1 and an exergonic character of 28.4 kcal·mol−1 that makes them irreversible and kinetically controlled. The most favorable reaction is that involving the most nucleophilic MeO-substituted NO. Despite Parr functions correctly predicting the experimental regioselectivity with the most favorable O-CCCl3 interaction, these reactions follow a two-stage one-step mechanism in which formation of the O-C(CCl3) bond takes place once the C-C(NO2) bond is already formed. The present MEDT concludes that the reactivity differences in the series of NOs come from their different nucleophilic activation and polar character of the reactions, rather than any mechanistic feature.

Understanding the molecular mechanism of the stereoselective conversion of N-trialkylsilyloxy nitronates into bicyclic isoxazoline derivatives

2021 ◽  
Author(s):  
Agnieszka Kącka-Zych ◽  
Radomir Jasinski
Keyword(s):  
Density Functional Theory ◽  
Molecular Mechanism ◽  
Electron Density ◽  
Density Functional ◽  
Dft Method ◽  
Functional Theory ◽  
Molecular Electron ◽  
Molecular Electron Density Theory

Conversion of N-trialkylsilyloxy nitronates into bicyclic isoxazoline derivatives has been explored using Density Functional Theory (DFT) method within the context of the Molecular Electron Density Theory (MEDT) at the B97XD(PCM)/6-311G(d,p)...

scholarly journals Unveiling the Unexpected Reactivity of Electrophilic Diazoalkanes in [3+2] Cycloaddition Reactions within Molecular Electron Density Theory

2020 ◽  
Author(s):  
Luis R. Domingo ◽  
Mar Ríos-Gutiérrez ◽  
Nivedita Acharjee
Keyword(s):  
Electron Density ◽  
Complete Agreement ◽  
Slowing Down ◽  
Molecular Electron ◽  
One Step ◽  
Molecular Electron Density Theory ◽  
Electrophilic Character ◽  
Step Mechanism ◽  
Computational Level ◽  
Density Transfer

The [3+2] cycloaddition (32CA) reactions of strongly nucleophilic norbornadiene (NBD) with simplest diazoalkane (DAA) and three DAAs of increased electrophilicity have been studied within the Molecular Electron Density Theory (MEDT) at the MPWB1K/6-311G(d,p) computational level. These pmr-type 32CA reactions follow an asynchronous one-step mechanism with activation enthalpies ranging from 17.7 to 27.9 kcal·mol-1 in acetonitrile. The high exergonic character of these reactions makes them irreversible. The presence of electron-withdrawing (EW) substituents in the DAA increases the activation enthalpies, in complete agreement with the experimental slowing-down of the reactions, but contrary to the Conceptual DFT prediction. Despite the nucleophilic and electrophilic character of the reagents, the global electron density transfer at the TSs indicates rather non-polar 32CA reactions. The present MEDT study allows establishing that the depopulation of the NNC core in this series of DAAs with the increase of the EW character of the substituents present at the carbon center is responsible for the experimentally found deceleration.

scholarly journals Understanding the Reactivity of Trimethylsilyldiazoalkanes Participating in [3+2] Cycloaddition Reactions towards Diethylfumarate with a Molecular Electron Density Theory Perspective

Organics ◽  
2020 ◽  
Vol 1 (1) ◽  
pp. 3-18
Author(s):  
Luis R. Domingo ◽  
Nivedita Acharjee ◽  
Haydar A. Mohammad-Salim
Keyword(s):  
Electron Density ◽  
Energy Cost ◽  
Trimethylsilyl Group ◽  
Gibbs Energies ◽  
Molecular Electron ◽  
One Step ◽  
Molecular Electron Density Theory ◽  
Non Covalent Interactions ◽  
Covalent Interactions ◽  
Step Mechanism

A Molecular Electron Density Theory (MEDT) study is presented here for [3+2] cycloaddition (32CA) reactions of three trimethylsilyldiazoalkanes with diethyl fumarate. The presence of silicon bonded to the carbon of these silyldiazoalkanes changes its structure and reactivity from a pseudomonoradical to that of a zwitterionic one. A one-step mechanism is predicted for these polar zw-type 32CA reactions with activation enthalpies in CCl4 between 8.0 and 19.7 kcal·mol−1 at the MPWB1K (PCM)/6-311G(d,p) level of theory. The negative reaction Gibbs energies between −3.1 and −13.2 kcal·mole−1 in CCl4 suggests exergonic character, making the reactions irreversible. Analysis of the sequential changes in the bonding pattern along the reaction paths characterizes these zw-type 32CA reactions. The increase in nucleophilic character of the trimethylsilyldiazoalkanes makes these 32CA reactions more polar. Consequently, the activation enthalpies are decreased and the TSs require less energy cost. Non-covalent interactions at the TSs account for the stereoselectivity found in these 32CA reactions involving the bulky trimethylsilyl group.

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