scholarly journals Highly Diastereo- and Enantioselective Synthesis of Quinuclidine Derivatives by an Iridium-Catalyzed Intramolecular Allylic Dearomatization Reaction

CCS Chemistry ◽  
2019 ◽  
pp. 106-116 ◽  
Author(s):  
Lin Huang ◽  
Yue Cai ◽  
Hui-Jun Zhang ◽  
Chao Zheng ◽  
Li-Xin Dai ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Catalytic System ◽  
Density Functional ◽  
Functional Group ◽  
Enantioselective Synthesis ◽  
Large Array ◽  
Functional Theory ◽  
Mild Conditions ◽  
Group Diversity

Asymmetric construction of quinuclidine derivatives has been realized by an iridium-catalyzed allylic dearomatization reaction. The catalytic system, derived from [Ir(cod)Cl] 2 and the Feringa ligand, tolerates a broad range of substrates. A large array of quinuclidine derivatives can be obtained under mild conditions in good to excellent yields (68%–96%), diastereoselectivity (up to >20/1 dr), and enantioselectivity (up to >99% ee). These products feature versatile functional group diversity and can undergo diverse transformations. A model that accounts for the origin of the stereoselectivity has been proposed based on density functional theory (DFT) calculations.

scholarly journals Dual Catalytic Enantioselective Desymmetrization of Allene-Tethered Cyclohexanones

2020 ◽  
Author(s):  
Lin Zhang ◽  
Ken Yamazaki ◽  
Jamie Leitch ◽  
Ruben Manzano ◽  
Victoria Atkinson ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Catalytic System ◽  
Density Functional ◽  
Functional Theory ◽  
Co Catalyst ◽  
Mechanistic Pathway

<p>The construction of enantioenriched azabicyclo[3.3.1]nonan-6-one heterocycles via an enantioselective desymmetrization of allene-linked cyclohexanones, enabled through a dual catalytic system, that provides synchronous activation of the cyclohexanone with a chiral prolinamide and the allene with a copper(I) co-catalyst to deliver the stereodefined bicyclic core, is described. Successful application to oxygen analogues was also achieved, thereby providing a new enantioselective synthetic entry to architecturally complex bicyclic ethereal frameworks. The mechanistic pathway and the origin of enantio- and diastereoselectivities has been uncovered using density functional theory (DFT) calculations.</p>

scholarly journals Functional Group Effects on the HOMO–LUMO Gap of g-C3N4

Nanomaterials ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 589 ◽  
Author(s):  
Hao Li ◽  
Zhien Zhang ◽  
Yulu Liu ◽  
Wanglai Cen ◽  
Xubiao Luo
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Band Gap ◽  
Density Functional ◽  
Carbon Nitride ◽  
Functional Group ◽  
Functional Theory ◽  
Metal Free ◽  
Homo Lumo ◽  
Group Effects

Graphitic carbon nitride (g-C3N4) is a promising semiconductor material which has been widely studied in nanoscience. However, the effect of modifying the performance of g-C3N4 is still under debate. In this communication, we show the size and functional group effects on the g-C3N4 using density functional theory (DFT) calculations. It was found that a molecule with six repeated g-C3N4 units (g-C3N4-6) could be the smallest unit that converges to the limit of its HOMO–LUMO gap. Calculations of g-C3N4-6 with varying numbers of substituted C≡N, C=O, and O−H functional groups show that C≡N and C=O could narrow down the HOMO–LUMO gap, while O−H could slightly raise the gap. This study shows that the change of substituents could tune the band gap of g-C3N4, suggesting that rationally modifying the substituent at the edge of g-C3N4-based materials could help to significantly increase the photocatalytic properties of a metal-free g-C3N4.

scholarly journals Highly Enantioselective Synthesis of Indazoles with a C3-Quaternary Chiral Center Using CuH Catalysis

2019 ◽  
Author(s):  
Yuxuan Ye ◽  
Ilia Kevlishvili ◽  
Sheng Feng ◽  
Peng Liu ◽  
Stephen L. Buchwald
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Transition State ◽  
Density Functional ◽  
Enantioselective Synthesis ◽  
Chiral Center ◽  
Functional Theory ◽  
Type Transition ◽  
Allyl Complex ◽  
Quaternary Stereocenters

<div><div><div><p>C3-substituted 1H-indazoles are useful and important substructures in many pharmaceuticals. Methods for direct C3- functionalization of indazoles are relatively rare, compared to reactions developed for the more nucleophilic N1 and N2 positions. Herein, we report a highly C3-selective allylation reaction of 1H-N-(benzoyloxy)indazoles using CuH catalysis. A variety of C3-allyl 1H-indazoles with quaternary stereocenters were efficiently prepared with high levels of enantioselectivity. Density functional theory (DFT) calculations suggest that the indazole addition to copper allyl complex proceeds through an enantioselectivity-determining six- membered Zimmerman-Traxler-type transition state. The enantioselectivity is governed both by the ligand-substrate steric interac- tions and the steric repulsions with the pseudoaxial substituent in the six-membered allylation transition state.</p></div></div></div>

A DFT-Weaving of Single Component Bifunctional Organocatalysts for Carbon dioxide/Propylene Oxide Coupling Reaction

2021 ◽  
Author(s):  
Morad El-Hendawy ◽  
Ibtesam Desoky ◽  
Mahmoud M. Mohamed
Keyword(s):  
Carbon Dioxide ◽  
Density Functional Theory ◽  
Dft Calculations ◽  
Propylene Oxide ◽  
Density Functional ◽  
Coupling Reaction ◽  
Single Component ◽  
Coupling Reactions ◽  
Functional Theory ◽  
Mild Conditions

The work aims to develop single-component bifunctional organic catalysts capable of effectively coupling reactions between CO2 and propylene epoxide (PO) under mild conditions using density functional theory (DFT) calculations. The...

scholarly journals Highly Enantioselective Synthesis of Indazoles with a C3-Quaternary Chiral Center Using CuH Catalysis

2019 ◽  
Author(s):  
Yuxuan Ye ◽  
Ilia Kevlishvili ◽  
Sheng Feng ◽  
Peng Liu ◽  
Stephen L. Buchwald
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Transition State ◽  
Density Functional ◽  
Enantioselective Synthesis ◽  
Chiral Center ◽  
Functional Theory ◽  
Type Transition ◽  
Allyl Complex ◽  
Quaternary Stereocenters

<div><div><div><p>C3-substituted 1H-indazoles are useful and important substructures in many pharmaceuticals. Methods for direct C3- functionalization of indazoles are relatively rare, compared to reactions developed for the more nucleophilic N1 and N2 positions. Herein, we report a highly C3-selective allylation reaction of 1H-N-(benzoyloxy)indazoles using CuH catalysis. A variety of C3-allyl 1H-indazoles with quaternary stereocenters were efficiently prepared with high levels of enantioselectivity. Density functional theory (DFT) calculations suggest that the indazole addition to copper allyl complex proceeds through an enantioselectivity-determining six- membered Zimmerman-Traxler-type transition state. The enantioselectivity is governed both by the ligand-substrate steric interac- tions and the steric repulsions with the pseudoaxial substituent in the six-membered allylation transition state.</p></div></div></div>

scholarly journals Dual Catalytic Enantioselective Desymmetrization of Allene-Tethered Cyclohexanones

2020 ◽  
Author(s):  
Lin Zhang ◽  
Ken Yamazaki ◽  
Jamie Leitch ◽  
Ruben Manzano ◽  
Victoria Atkinson ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Catalytic System ◽  
Density Functional ◽  
Functional Theory ◽  
Co Catalyst ◽  
Mechanistic Pathway

<p>The construction of enantioenriched azabicyclo[3.3.1]nonan-6-one heterocycles via an enantioselective desymmetrization of allene-linked cyclohexanones, enabled through a dual catalytic system, that provides synchronous activation of the cyclohexanone with a chiral prolinamide and the allene with a copper(I) co-catalyst to deliver the stereodefined bicyclic core, is described. Successful application to oxygen analogues was also achieved, thereby providing a new enantioselective synthetic entry to architecturally complex bicyclic ethereal frameworks. The mechanistic pathway and the origin of enantio- and diastereoselectivities has been uncovered using density functional theory (DFT) calculations.</p>

γ-Valerolactone-Introduced Controlled-Isomerization of Glucose for Lactic Acid Production over Sn-Beta Catalyst

2021 ◽  
Author(s):  
Xinpeng Zhao ◽  
Zhimin Zhou ◽  
hu luo ◽  
Yanfei Zhang ◽  
Wang Liu ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Lactic Acid ◽  
Dft Calculations ◽  
Acid Production ◽  
Density Functional ◽  
Lactic Acid Production ◽  
Hydrothermal Conversion ◽  
Functional Theory ◽  
Environment Friendly

Combined experiments and density functional theory (DFT) calculations provided insights into the role of the environment-friendly γ-valerolactone (GVL) as a solvent in the hydrothermal conversion of glucose into lactic acid...

Mechanistic understanding of the Cu(i)-catalyzed domino reaction constructing 1-aryl-1,2,3-triazole from electron-rich aryl bromide, alkyne, and sodium azide: a DFT study

2021 ◽  
Author(s):  
Hanlin Gan ◽  
Liang Peng ◽  
Feng Long Gu
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Sodium Azide ◽  
Density Functional ◽  
Dft Study ◽  
Domino Reaction ◽  
Aryl Bromide ◽  
Functional Theory ◽  
Mechanistic Understanding

The mechanism of the Cu(i)-catalyzed domino reaction furnishing 1-aryl-1,2,3-triazole assisted by CuI and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) is explored with density functional theory (DFT) calculations.

scholarly journals Density functional theory (DFT) calculations of VI/V reduction potentials of uranyl coordination complexes in non-aqueous solutions

2019 ◽  
Vol 21 (6) ◽  
pp. 3227-3241 ◽  
Author(s):  
Krishnamoorthy Arumugam ◽  
Neil A. Burton
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Aqueous Solutions ◽  
Density Functional ◽  
Coordination Complexes ◽  
Dft Study ◽  
Redox Behavior ◽  
Functional Theory ◽  
Reduction Potentials ◽  
Uranium Complexes

Of particular interest within the +6 uranium complexes is the linear uranyl(vi) cation and it forms numerous coordination complexes in solution and exhibits incongruent redox behavior depending on coordinating ligands. This DFT study predicts VI/V reduction potentials of a range of uranyl(vi) complexes in non-aqueous solutions within ∼0.10−0.20 eV of experiment.

scholarly journals Iron(II) complexes of dimethyltriazacyclophane

2018 ◽  
Vol 74 (12) ◽  
pp. 1641-1649
Author(s):  
Wei-Tsung Lee ◽  
Matthias Zeller ◽  
David Upp ◽  
Yuliya Politanska ◽  
Doug Steinman ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Solid State ◽  
Dft Calculations ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Coordination Mode ◽  
Functional Theory ◽  
Metal Centers ◽  
Bonding Interaction

Treatment of the ortho-triazacyclophane 1,4-dimethyltribenzo[b,e,h][1,4,7]triazacyclonona-2,5,8-triene [(C6H5)3(NH)(NCH3)2, L1] with Fe[N(SiMe3)2]2 yields the dimeric iron(II) complex bis(μ-1,4-dimethyltribenzo[b,e,h][1,4,7]triazacyclonona-2,5,8-trien-7-ido)bis[(μ-1,4-dimethyltribenzo[b,e,h][1,4,7]triazacyclonona-2,5,8-trien-7-ido)iron(II)], [Fe(C20H18N3)4] or Fe2(L1)4 (9). Dissolution of 9 in tetrahydrofuran (THF) results in solvation by two THF ligands and the formation of a simpler monoiron complex, namely bis(μ-1,4-dimethyltribenzo[b,e,h][1,4,7]triazacyclonona-2,5,8-trien-7-ido-κN 7)bis(tetrahydrofuran-κO)iron(II), [Fe(C20H18N3)2(C4H8O)2] or (L1)2Fe(THF)2 (10). The reaction is reversible and 10 reverts in vacuo to diiron complex 9. In the structures of both 9 and 10, the monoanionic triazacyclophane ligand L1− is observed in only the less-symmetric saddle conformation. No bowl-shaped crown conformers are observed in the solid state, thus preventing chelating κ3-coordination to the metal as had been proposed earlier based on density functional theory (DFT) calculations. Instead, the L1− ligands are bound in either a η2-chelating fashion through the amide and one amine donor (for one of the four ligands of 9), or solely through their amide N atoms in an even simpler monodentate η1-coordination mode. Density functional calculations on dimer 9 revealed nearly full cationic charges on each Fe atom and no bonding interaction between the two metal centers, consistent with the relatively long Fe...Fe distance of 2.912 (1) Å observed in the solid state.

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