The Influence of Various Solvents on Energetic Property and Stability in C5H4 Divalent Five-Membered Ring: A DFT Studies

2012 ◽  
Vol 28 (3) ◽  
pp. 1331-1343 ◽  
Author(s):  
REZA SOLEYMANI ◽  
KHALIL GHESMAT KONANDEH ◽  
REIHANEH DEHGHANIAN DIJVEJIN
Keyword(s):  
Membered Ring ◽  
Dft Studies ◽  
Energetic Property

Three-Coordinate Nickel(I) Complexes Stabilised by Six-, Seven- and Eight-Membered Ring N-Heterocyclic Carbenes: Synthesis, EPR/DFT Studies and Catalytic Activity

2013 ◽  
Vol 19 (6) ◽  
pp. 2158-2167 ◽  
Author(s):  
Michael J. Page ◽  
Wei Y. Lu ◽  
Rebecca C. Poulten ◽  
Emma Carter ◽  
Andrés G. Algarra ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Membered Ring ◽  
Heterocyclic Carbenes ◽  
Dft Studies

DFT studies on the mechanism of acetylene hydrochlorination over gold-based catalysts and guidance for catalyst construction

2019 ◽  
Vol 6 (10) ◽  
pp. 2944-2952 ◽  
Author(s):  
Chaoyue Zhao ◽  
Qingxin Guan ◽  
Wei Li
Keyword(s):  
Transition State ◽  
Linear Structure ◽  
Membered Ring ◽  
Dft Studies ◽  
Acetylene Hydrochlorination ◽  
Ring Transition State ◽  
Catalyst Construction

In the presence of both HCl and C2H2, the linear structure of AuCl is proposed to form a tetracoordinated five-membered ring transition state, along with the oxidation of the Au center from Au(i) into Au(iii).

Eight-membered-ring diaminocarbenes bearing naphthalene moiety in the backbone: DFT studies, synthesis of amidinium salts, generation of free carbene, metal complexes, and solvent-free copper catalyzed azide–alkyne cycloaddition (CuAAC) reaction

2017 ◽  
Vol 46 (13) ◽  
pp. 4331-4345 ◽  
Author(s):  
Gleb A. Chesnokov ◽  
Maxim A. Topchiy ◽  
Pavel B. Dzhevakov ◽  
Pavel S. Gribanov ◽  
Aleksandr A. Tukov ◽  
...  
Keyword(s):  
Metal Complexes ◽  
Membered Ring ◽  
Solvent Free ◽  
Dft Studies ◽  
Cuaac Reaction ◽  
New Type

A new type of eight-membered NHC.

DFT studies on quantum mechanical tunneling in tautomerization of three-membered rings

2018 ◽  
Vol 20 (44) ◽  
pp. 28049-28058
Author(s):  
Kalyanashis Jana ◽  
Bishwajit Ganguly
Keyword(s):  
Dft Calculations ◽  
Membered Ring ◽  
Quantum Mechanical ◽  
Dft Studies ◽  
Quantum Mechanical Tunneling ◽  
Ring Systems ◽  
Tautomeric Forms ◽  
Shed Light

Amino–imino and keto–enol tautomerization processes in three-membered ring systems have been explored to examine the role of quantum mechanical tunneling along with aromaticity. The DFT calculations shed light on the role of aromaticity in tautomerization processes and as perceived this property may not contribute entirely to facilitate the formation of tautomeric forms.

Stereodivergent Alkyne Hydrofluorination Using a Simple Practical Reagent

2020 ◽  
Author(s):  
Rui Guo ◽  
Xiaotian Qi ◽  
Hengye Xiang ◽  
Paul Geaneoates ◽  
Ruihan Wang ◽  
...  
Keyword(s):  
Bond Formation ◽  
Biologically Active ◽  
Dft Studies ◽  
Thermodynamic Control ◽  
Important Goal ◽  
Peptide Bonds ◽  
Metal Free ◽  
Vinyl Cation ◽  
E And Z Isomers ◽  
Vinyl Fluorides

Vinyl fluorides play an important role in drug development as they serve as bioisosteres for peptide bonds and are found in a range of biologically active molecules. The discovery of safe, general and practical procedures to prepare vinyl fluorides remains an important goal and challenge for synthetic chemistry. Here we introduce an inexpensive and easily-handled reagent and report simple, scalable, and metal-free protocols for the regioselective and stereodivergent hydrofluorination of alkynes to access both the E and Z isomers of vinyl fluorides. These conditions were suitable for a diverse collection of alkynes, including several highly-functionalized pharmaceutical derivatives. Mechanistic and DFT studies support C–F bond formation through a vinyl cation intermediate, with the (E)- and (Z)-hydrofluorination products forming under kinetic and thermodynamic control, respectively.<br>

Copper Catalyzed sp3 C-H α-Acetylation

2019 ◽  
Author(s):  
Otome Okoromoba ◽  
Eun Sil Jang ◽  
Claire McMullin ◽  
Thomas Cundari ◽  
Timothy H. Warren
Keyword(s):  
Natural Products ◽  
Dft Studies ◽  
Alkyl Radicals ◽  
Important Chemical ◽  
Alkyl Electrophiles ◽  
Synthetic Intermediates ◽  
Alkylation Reactions

<p>α-substituted ketones are important chemical targets as synthetic intermediates as well as functionalities in in natural products and pharmaceuticals. We report the sp<sup>3</sup> C-H α-acetylation of sp<sup>3</sup> C-H substrates R-H with arylmethyl ketones ArC(O)Me to provide α-alkylated ketones ArC(O)CH<sub>2</sub>R at RT with <sup>t</sup>BuOO<sup>t</sup>Bu as oxidant via copper(I) β-diketiminato catalysts. Proceeding via alkyl radicals R•, this method enables α-substitution with bulky substituents without competing elimination that occurs in more traditional alkylation reactions between enolates and alkyl electrophiles. DFT studies suggest the intermediacy of copper(II) enolates [Cu<sup>II</sup>](CH<sub>2</sub>C(O)Ar) that capture alkyl radicals R• to give R-CH<sub>2</sub>C(O)Ar under competing dimerization of the copper(II) enolate to give the 1,4-diketone ArC(O)CH<sub>2</sub>CH<sub>2</sub>C(O)Ar.</p>

Copper Catalyzed sp3 C-H α-Acetylation

2019 ◽  
Author(s):  
Otome Okoromoba ◽  
Eun Sil Jang ◽  
Claire McMullin ◽  
Thomas Cundari ◽  
Timothy H. Warren
Keyword(s):  
Natural Products ◽  
Dft Studies ◽  
Alkyl Radicals ◽  
Important Chemical ◽  
Alkyl Electrophiles ◽  
Synthetic Intermediates ◽  
Alkylation Reactions

<p>α-substituted ketones are important chemical targets as synthetic intermediates as well as functionalities in in natural products and pharmaceuticals. We report the sp<sup>3</sup> C-H α-acetylation of sp<sup>3</sup> C-H substrates R-H with arylmethyl ketones ArC(O)Me to provide α-alkylated ketones ArC(O)CH<sub>2</sub>R at RT with <sup>t</sup>BuOO<sup>t</sup>Bu as oxidant via copper(I) β-diketiminato catalysts. Proceeding via alkyl radicals R•, this method enables α-substitution with bulky substituents without competing elimination that occurs in more traditional alkylation reactions between enolates and alkyl electrophiles. DFT studies suggest the intermediacy of copper(II) enolates [Cu<sup>II</sup>](CH<sub>2</sub>C(O)Ar) that capture alkyl radicals R• to give R-CH<sub>2</sub>C(O)Ar under competing dimerization of the copper(II) enolate to give the 1,4-diketone ArC(O)CH<sub>2</sub>CH<sub>2</sub>C(O)Ar.</p>

An Alternate Energy-Conserved Pathway for the Morita-Baylis-Hillman (MBH) Reaction

2020 ◽  
Author(s):  
Veejendra Yadav
Keyword(s):  
Proton Transfer ◽  
Transition State ◽  
Lower Energy ◽  
Aldol Reaction ◽  
Membered Ring ◽  
Ammonium Ion ◽  
Alternate Energy ◽  
Ring Transition State ◽  
Mbh Reaction

An new overall lower energy pathway for the amine-catalysed Morita-Baylis-Hillman reaction is proposed from computations at the M06-2X/6-311++G(d,p) level. The pathway involves proton-transfer from the ammonium ion to the alkoxide formed from the aldol reaction through a seven-membered ring transition state (TS) structure followed by highly exothermic Hofmann<i> </i>elimination through a five-membered ring TS structure to form the product and also release the catalyst to carry on with the process all over again.

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