Origins of ligand-controlled diastereoselectivity in dirhodium-catalysed direct amination of aliphatic C(sp3)–H bonds

2021 ◽  
Author(s):  
Qiannan Li ◽  
Wenjing Liu ◽  
Yanfeng Dang
Keyword(s):  
Dft Calculations ◽  
Direct Amination ◽  
Catalytic Cycles

The mechanism and origins of ligand-controlled stereoselectivity of dirhodium (Rh2L4, L=OAc, S-tertPTTL)-catalysed intramolecular aliphatic C(sp3)−H aminations have been explored using DFT calculations. Both catalytic cycles occur via the formation of...

Catalytic Cycles for the Reduction of [UO2]2+by Cytochromec7Proteins Proposed from DFT Calculations

2008 ◽  
Vol 112 (19) ◽  
pp. 4451-4457 ◽  
Author(s):  
Mahesh Sundararajan ◽  
Andrew J. Campbell ◽  
Ian H Hillier
Keyword(s):  
Dft Calculations ◽  
Catalytic Cycles

scholarly journals Fast and Green Method to Synthesis of Quinolone Carboxylic Acid Derivatives Using Giant-Ball Nanoporous Isopolyoxomolybdate as Highly Efficient Recyclable Catalyst in Refluxing Water

2017 ◽  
Vol 61 (1) ◽  
Author(s):  
Yahya Mirzaie ◽  
Jalil Lari ◽  
Hooshang Vahedi ◽  
Mohammad Hakimi ◽  
Ahmad Nakhaei ◽  
...  
Keyword(s):  
Reaction Time ◽  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Reaction Times ◽  
Green Method ◽  
Direct Amination ◽  
Short Reaction Time ◽  
Piperazine Derivatives ◽  
Type Giant ◽  
Catalytic Cycles

Various potentials antibacterial fluoroquinolone compounds were prepared by the direct amination of 7-halo-6- fluoroquinolone-3-carboxylic acids with variety of piperazine derivatives and (4aR,7aR)-octahydro-1H-pyrrolo[3,4-b] pyridine using (NH<sub>4</sub>)<sub>42</sub> [Mo<sup>VI</sup><sub>72</sub>Mo<sup>V</sup><sub>60</sub>O<sub>372</sub>(CH<sub>3</sub>COO)<sub>30</sub>(H<sub>2</sub>O)<sub>72</sub>], a Keplerate-type giant-ball nanoporous isopolyoxomolybdate, as a catalyst in refluxing water. The results showed that this catalyst acts as effective catalyst and the reaction proceeded more easily and gave the highest yields of the products in short reaction time under refluxing water. Short reaction times, simple isolation of the products, and usage of eco-friendly catalysts are some features of this procedure. In addition, the catalysts was easily recovered and used in multiple catalytic cycles. This material was prepared according to a previously published literature procedure using inexpensive and readily available starting materials.

Relative stabilities of M/NHC complexes (M = Ni, Pd, Pt) against R–NHC, X–NHC and X–X couplings in M(0)/M(ii) and M(ii)/M(iv) catalytic cycles: a theoretical study

2019 ◽  
Vol 48 (45) ◽  
pp. 17052-17062 ◽  
Author(s):  
Alexander V. Astakhov ◽  
Safarmurod B. Soliev ◽  
Evgeniy G. Gordeev ◽  
Victor M. Chernyshev ◽  
Valentine P. Ananikov
Keyword(s):  
Dft Calculations ◽  
Relative Stability ◽  
Theoretical Study ◽  
Reductive Elimination ◽  
Catalyst Stability ◽  
Relative Stabilities ◽  
Elimination Reactions ◽  
Catalytic Cycles

DFT calculations reveal relative stability of MII/NHC and MIV/NHC complexes of nickel, palladium and platinum against the R–NHC coupling and various reductive elimination reactions that influence catalyst stability/decomposition.

Structure elucidation of a proton-deficient natural product using LR-HSQMBC supported by DFT calculations

Planta Medica ◽  
2015 ◽  
Vol 81 (11) ◽  
Author(s):  
J Saurí ◽  
STS Chan ◽  
AV Buevich ◽  
KR Gustafson ◽  
RT Williamson ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Natural Product ◽  
Structure Elucidation

Reactions of an Aluminium(I) Reagent with 1,2-, 1,3- and 1,5-Dienes: Dearomatisation, Reversibility, and a Pericyclic Mechanism

2019 ◽  
Author(s):  
Clare Bakewell ◽  
Martí Garçon ◽  
Richard Y Kong ◽  
Louisa O'Hare ◽  
Andrew J. P. White ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Dft Calculations ◽  
Transition State ◽  
Reaction Pathways ◽  
Aromatic Rings ◽  
Aromatic Character ◽  
Pericyclic Reaction

The reactions of an aluminium(I) reagent with a series of 1,2-, 1,3- and 1,5-dienes are reported. In the case of 1,3-dienes the reaction occurs by a pericyclic reaction mechanism, specifically a cheletropic cycloaddition, to form aluminocyclopentene containing products. This mechanism has been interrogated by stereochemical experiments and DFT calculations. The stereochemical experiments show that the (4+1) cycloaddition follows a suprafacial topology, while calculations support a concerted albeit asynchronous pathway in which the transition state demonstrates aromatic character. Remarkably, the substrate scope of the (4+1) cycloaddition includes dienes that are either in part, or entirely, contained within aromatic rings. In these cases, reactions occur with dearomatisation of the substrate and can be reversible. In the case of 1,2- or 1,5-dienes complementary reactivity is observed; the orthogonal nature of the C=C π-bonds (1,2-diene) and the homoconjugated system (1,5-diene) both disfavour a (4+1) cycloaddition. Rather, reaction pathways are determined by an initial (2+1) cycloaddition to form an aluminocyclopropane intermediate which can in turn undergo insertion of a further C=C π-bond leading to complex organometallic products that incorporate fused hydrocarbon rings.

Reversible Oxidative-Addition and Reductive-Elimination of Thiophene from a Titanium Complex and Its Thermally-Induced Hydrodesulfurization Chemistry

2019 ◽  
Author(s):  
Alejandra Gomez-Torres ◽  
J. Rolando Aguilar-Calderón ◽  
Carlos Saucedo ◽  
Aldo Jordan ◽  
Alejandro J. Metta-Magaña ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Ring Opening ◽  
Thiophene Ring ◽  
Oxidative Addition ◽  
Reductive Elimination ◽  
Thermally Induced ◽  
Titanium Complex

<p>The masked Ti(II) synthon (<sup>Ket</sup>guan)(<i>η</i><sup>6</sup>-Im<sup>Dipp</sup>N)Ti (<b>1</b>) oxidatively adds across thiophene to give ring-opened (<sup>Ket</sup>guan)(Im<sup>Dipp</sup>N)Ti[<i>κ</i><sup>2</sup>-<i>S</i>(CH)<sub>3</sub><i>C</i>H] (<b>2</b>). Complex <b>2</b> is photosensitive, and upon exposure to light, reductively eliminates thiophene to regenerate <b>1</b> – a rare example of early-metal mediated oxidative-addition/reductive-elimination chemistry. DFT calculations indicate strong titanium π-backdonation to the thiophene π*-orbitals leads to the observed thiophene ring opening across titanium, while a proposed photoinduced LMCT promotes the reverse thiophene elimination from <b>2</b>. Finally, pressurizing solutions of <b>2 </b>with H<sub>2</sub> (150 psi) at 80 °C leads to the hydrodesulfurization of thiophene to give the Ti(IV) sulfide (<sup>Ket</sup>guan)(Im<sup>Dipp</sup>N)Ti(S) (<b>3</b>) and butane. </p>

Solvent Dependence of Structural Dynamics and Spin-flip Processes in 3,4,5-tri(9H-carbazole-9-yl)benzonitrile (ortho-3CzBN)

2020 ◽  
Author(s):  
Masaki Saigo ◽  
Kiyoshi Miyata ◽  
Hajime Nakanotani ◽  
Chihaya Adachi ◽  
Ken Onda
Keyword(s):  
Dft Calculations ◽  
Excited States ◽  
Structural Changes ◽  
Photophysical Properties ◽  
Delayed Fluorescence ◽  
Time Resolved ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Solvent Dependence ◽  
Acetonitrile Solutions

We have investigated the solvent-dependence of structural changes along with intersystem crossing of a thermally activated delayed fluorescence (TADF) molecule, 3,4,5-tri(9H-carbazole-9-yl)benzonitrile (o-3CzBN), in toluene, tetrahydrofuran, and acetonitrile solutions using time-resolved infrared (TR-IR) spectroscopy and DFT calculations. We found that the geometries of the S1 and T1 states are very similar in all solvents though the photophysical properties mostly depend on the solvent. In addition, the time-dependent DFT calculations based on these geometries suggested that the thermally activated delayed fluorescence process of o-3CzBN is governed more by the higher-lying excited states than by the structural changes in the excited states.<br>

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