Electrophilic aromatic substitution reactions of compounds with Craig-Möbius aromaticity

2021 ◽  
Vol 118 (39) ◽  
pp. e2102310118
Author(s):  
Yuanting Cai ◽  
Yuhui Hua ◽  
Zhengyu Lu ◽  
Qing Lan ◽  
Zuzhang Lin ◽  
...  
Keyword(s):  
Density Functional ◽  
Electronic Effect ◽  
Density Functional Theory Calculations ◽  
Electrophilic Aromatic Substitution ◽  
Aromatic Substitution ◽  
Substitution Reactions ◽  
Electrophilic Attack ◽  
Functional Theory ◽  
Aromatic Species ◽  
Selective Formation

Electrophilic aromatic substitution (EAS) reactions are widely regarded as characteristic reactions of aromatic species, but no comparable reaction has been reported for molecules with Craig-Möbius aromaticity. Here, we demonstrate successful EAS reactions of Craig-Möbius aromatics, osmapentalenes, and fused osmapentalenes. The highly reactive nature of osmapentalene makes it susceptible to electrophilic attack by halogens, thus osmapentalene, osmafuran-fused osmapentalene, and osmabenzene-fused osmapentalene can undergo typical EAS reactions. In addition, the selective formation of a series of halogen substituted metalla-aromatics via EAS reactions has revealed an unprecedented approach to otherwise elusive compounds such as the unsaturated cyclic chlorirenium ions. Density functional theory calculations were conducted to study the electronic effect on the regioselectivity of the EAS reactions.

Mechanism of nucleophilic substitution reactions of 4-(4ˊ-nitro)phenylnitrobenzofurazan ether with aniline in acetonitrile.

2017 ◽  
Vol 2 (10) ◽  
Author(s):  
K. Gbayo ◽  
C. Isanbor ◽  
K. Lobb ◽  
O. Oloba-Whenu
Keyword(s):  
Density Functional Theory ◽  
Nuclear Magnetic Resonance ◽  
Density Functional ◽  
Theoretical Study ◽  
Activation Parameters ◽  
Nucleophilic Aromatic Substitution ◽  
Aromatic Substitution ◽  
Substitution Reactions ◽  
Functional Theory ◽  
Nmr Techniques

Abstract Rate constants and activation parameters obtained for the nucleophilic aromatic substitution reactions (SNAr) of 4-substitutedphenoxy-7-nitrobenzoxadiazole (1) with aniline in acetonitrile at varying temperature using Nuclear Magnetic Resonance (NMR) techniques were reported. These results were compared with the theoretical study which identifies transformations and intermediates using Density Functional Theory (DFT).

Nucleophilic Substitution Reactions of Cyclic Thiosulfinates Are Accelerated by Hyperconjugative Interactions

2019 ◽  
Author(s):  
Daniel Donnelly ◽  
Jeffrey Agar ◽  
Steven Lopez
Keyword(s):  
Density Functional Theory ◽  
Nucleophilic Substitution ◽  
Strain Energy ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Free Energies ◽  
Substitution Reactions ◽  
Functional Theory ◽  
Nucleophilic Substitution Reactions

Strain energy has been shown to promote the nucleophilic substitution reactions of cyclic disulfides, the reactivities of cyclic thiosulfinate nucleophilic substitution is unexplored. We used density functional theory calculations [M06-2X/6-311++G(d,p)] to determine the activation and reaction free energies for the reactions of 3—10-membered cyclic thiosulfinates and cyclic disulfides with methyl thiolate.

Nucleophilic Substitution Reactions of Cyclic Thiosulfinates Are Accelerated by Hyperconjugative Interactions

2019 ◽  
Author(s):  
Daniel Donnelly ◽  
Jeffrey Agar ◽  
Steven Lopez
Keyword(s):  
Density Functional Theory ◽  
Nucleophilic Substitution ◽  
Strain Energy ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Free Energies ◽  
Substitution Reactions ◽  
Functional Theory ◽  
Nucleophilic Substitution Reactions

Strain energy has been shown to promote the nucleophilic substitution reactions of cyclic disulfides, the reactivities of cyclic thiosulfinate nucleophilic substitution is unexplored. We used density functional theory calculations [M06-2X/6-311++G(d,p)] to determine the activation and reaction free energies for the reactions of 3—10-membered cyclic thiosulfinates and cyclic disulfides with methyl thiolate.

scholarly journals A Concise Synthesis of a Methyl Ester 2-Resorcinarene: A Chair-Conformation Macrocycle

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 627
Author(s):  
Michael R. Reynolds ◽  
Fraser S. Pick ◽  
John J. Hayward ◽  
John F. Trant
Keyword(s):  
Hydrogen Bond ◽  
Density Functional ◽  
Chair Conformation ◽  
Electrophilic Aromatic Substitution ◽  
Aromatic Substitution ◽  
Functional Theory ◽  
Design And Synthesis ◽  
Hydrogen Bond Strength ◽  
Recognition Elements ◽  
Configurational Isomerism

Anions are important hydrogen bond acceptors in a range of biological, chemical, environmental and medical molecular recognition processes. These interactions have been exploited for the design and synthesis of ditopic resorcinarenes as the hydrogen bond strength can be tuned through the modification of the substituent at the 2-position. However, many potentially useful compounds, especially those incorporating electron-withdrawing functionalities, have not been prepared due to the challenge of their synthesis: their incorporation slows resorcinarene formation that is accessed by electrophilic aromatic substitution. As part of our broader campaign to employ resorcinarenes as selective recognition elements, we need access to these specialized materials. In this article, we report a straightforward synthetic pathway for obtaining a 2-(carboxymethyl)-resorcinarene, and resorcinarene esters in general. We discuss the unusual conformation it adopts and propose that this arises from the electron-withdrawing nature of the ester substituents that renders them better hydrogen bond acceptors than the phenols, ensuring that each of them acts as a donor only. Density Functional Theory (DFT) calculations show that this conformation arises as a consequence of the unusual configurational isomerism of this compound and interruption of the archetypal hydrogen bonding by the ester functionality.

Theoretical Investigation on the Kinetics and Mechanism of the Synthesis of Fluorescent 3,8-Disubstituted-3H-Imidazo [4,5-a] Acridine-11-Carbonitriles

2016 ◽  
Vol 41 (4) ◽  
pp. 365-370 ◽  
Author(s):  
Fatemeh Zonozi ◽  
Mehdi Pordel ◽  
S. Ali Beyramabadi ◽  
Ali Morsali
Keyword(s):  
Theoretical Investigation ◽  
Density Functional ◽  
Theoretical Study ◽  
Fluorescent Dyes ◽  
Quantum Yields ◽  
Electrophilic Aromatic Substitution ◽  
Aromatic Substitution ◽  
Dft Methods ◽  
Functional Theory ◽  
Plausible Mechanism

3,8-Disubstituted-3H-imidazo[4,5-a]acridine-11-carbonitriles show very interesting optical properties. In some cases, they have higher quantum yields compared to well-known fluorescent dyes such as fluorescein. Hitherto, no detailed theoretical study has been reported on the mechanism of the synthesis of the titled compounds, hence an accurate and detailed theoretical investigation on the synthesis of these dyes is desirable. In this paper, density functional theory (DFT) methods have been employed to investigate the most reasonable mechanism in formation of these fluorophores. All species and related transition states were optimised and the relative energies of all species and the activation energies for all proposed mechanisms were obtained. Comparing the Ea values of all pathways reveals that intramolecular electrophilic aromatic substitution is the most plausible mechanism for the cyclisation reaction in the preparation of these dyes. Also, the effects of substituents in positions 3 and 8 were investigated and the results show that electron-donor substituents can reduce the activation energy for formation of the σ complex in the electrophilic aromatic substitution.

scholarly journals Desulfination by 2′-hydroxybiphenyl-2-sulfinate desulfinase proceeds via electrophilic aromatic substitution by the cysteine-27 proton

2017 ◽  
Vol 8 (7) ◽  
pp. 5078-5086 ◽  
Author(s):  
Inacrist Geronimo ◽  
Shawn R. Nigam ◽  
Christina M. Payne
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Electrophilic Substitution ◽  
Electrophilic Aromatic Substitution ◽  
Aromatic Substitution ◽  
Functional Theory ◽  
Rate Limiting

Density functional theory shows that the rate-limiting desulfination step in biodesulfurization involves concerted electrophilic substitution with the Cys-27 proton.

On the Linear Geometry of Lanthanide Hydroxide (Ln—OH, Ln=La-Lu)

2019 ◽  
Author(s):  
Hassan Harb ◽  
Lee Thompson ◽  
Hrant Hratchian
Keyword(s):  
Triple Bond ◽  
Density Functional ◽  
Valence Electron ◽  
Density Functional Theory Calculations ◽  
Electron Configuration ◽  
Functional Theory ◽  
Key Species ◽  
Pi Orbitals ◽  
Lanthanide Hydroxide ◽  
Linear Geometry

Lanthanide hydroxides are key species in a variety of catalytic processes and in the preparation of corresponding oxides. This work explores the fundamental structure and bonding of the simplest lanthanide hydroxide, LnOH (Ln=La-Lu), using density functional theory calculations. Interestingly, the calculations predict that all structures of this series will be linear. Furthermore, these results indicate a valence electron configuration featuring an occupied sigma orbital and two occupied pi orbitals for all LnOH compounds, suggesting that the lanthanide-hydroxide bond is best characterized as a covalent triple bond.

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