Theoretical study on the mechanism and enantioselectivity of NHC-catalyzed intramolecular SN2′ nucleophilic substitution: what are the roles of NHC and DBU?

2018 ◽  
Vol 5 (9) ◽  
pp. 1493-1501 ◽  
Author(s):  
Huimin Zhang ◽  
Hao Xu ◽  
Huining Bai ◽  
Donghui Wei ◽  
Yanyan Zhu ◽  
...  
Keyword(s):  
Nucleophilic Substitution ◽  
Catalytic Mechanism ◽  
Theoretical Study ◽  
Dft Method

A possible catalytic mechanism was proposed and studied in very detail by using the DFT method for a recently reported enantioselective intramolecular SN2′ substitution of aldehydes with trisubstituted allylic bromides.

scholarly journals Theoretical Study of the Reaction of Formation of Some Free Phosphines by Stereoselective Hydrophosphination through DFT Method

2018 ◽  
pp. 1-10
Author(s):  
Kouadio Valery Bohoussou ◽  
Anoubilé Bénié ◽  
Mamadou Guy-Richard Koné ◽  
N’guessan Yao Silvère Diki ◽  
Kafoumba Bamba ◽  
...  
Keyword(s):  
Theoretical Study ◽  
Chemical Reactivity ◽  
Dft Method ◽  
Trans Form ◽  
Dft Methods ◽  
Activation Barriers ◽  
Reactivity Descriptors ◽  
Chemical Reactivity Descriptors ◽  
Theoretical Results ◽  
Cis Isomer

In this work the formation of vinylphosphines was studied through the hydrophosphination reaction. The study aims to rationalize the stereoselectivity of these compounds using quantum DFT methods. This theoretical study of chemical reactivity was conducted at B3LYP/6-311 + G (d, p) level. Global chemical reactivity descriptors, stationary point energies and activation barriers were examined to foretell the relative stability of the stereoisomers formed. The various results obtained have revealed that the addition of arylphosphine to dihalogenoacetylene is stereospecific. The Trans form of vinylphosphines is more stable than the Cis form, when the substituent on phosphorus generates less or no π-conjugations. On the other hand, the Cis isomer is predominant when the aryl radical favors more π-conjugations. The theoretical results obtained are in agreement with the experimental results.

Theoretical Study of Nucleophilic Substitution at Two-Coordinate Sulfur

2001 ◽  
Vol 66 (6) ◽  
pp. 2005-2010 ◽  
Author(s):  
Steven M. Bachrach ◽  
BettyCep D. Gailbreath
Keyword(s):  
Nucleophilic Substitution ◽  
Theoretical Study

Catalytic Mechanism of Calcium on the Formation of HCN during Pyrolysis of Pyrrole and Indole: A Theoretical Study

2019 ◽  
Vol 33 (11) ◽  
pp. 11516-11523 ◽  
Author(s):  
Ji Liu ◽  
Xin-rui Fan ◽  
Wei Zhao ◽  
Bin Hu ◽  
Ding-jia Liu ◽  
...  
Keyword(s):  
Catalytic Mechanism ◽  
Theoretical Study

Why does tautomycetin thioesterase prefer hydrolysis to macrocyclization? Theoretical study on its catalytic mechanism

2019 ◽  
Vol 9 (22) ◽  
pp. 6391-6403
Author(s):  
Lei Liu ◽  
Wentao Tao ◽  
Linquan Bai ◽  
Eung-Soo Kim ◽  
Yi-Lei Zhao ◽  
...  
Keyword(s):  
Molecular Basis ◽  
Catalytic Mechanism ◽  
Theoretical Study

In this study, we attempted to uncover the reasons why Tautomycetin thioesterase (TMC TE) prefers hydrolysis rather than macrocyclization, and reveal the molecular basis of TE-catalyzed hydrolysis and macrocyclization.

Catalytic Mechanism of Glyoxalase I:  A Theoretical Study

2001 ◽  
Vol 123 (42) ◽  
pp. 10280-10289 ◽  
Author(s):  
Fahmi Himo ◽  
Per E. M. Siegbahn
Keyword(s):  
Catalytic Mechanism ◽  
Theoretical Study ◽  
Glyoxalase I

Catalytic mechanism of UDP-glucose dehydrogenase

2019 ◽  
Vol 47 (3) ◽  
pp. 945-955 ◽  
Author(s):  
Jun Chen ◽  
Shulin Yang
Keyword(s):  
Nucleophilic Substitution ◽  
Catalytic Mechanism ◽  
Glucuronic Acid ◽  
Glucose Dehydrogenase ◽  
Extensive Investigation ◽  
Oxidation Reactions ◽  
Oxidation Step ◽  
Sn2 Reaction ◽  
Experimental Findings

AbstractUDP-glucose dehydrogenase (UGDH), an oxidoreductase, catalyzes the NAD+-dependent four-electron oxidation of UDP-glucose to UDP-glucuronic acid. The catalytic mechanism of UGDH remains controversial despite extensive investigation and is classified into two types according to whether an aldehyde intermediate is generated in the first oxidation step. The first type, which involves the presence of this putative aldehyde, is inconsistent with some experimental findings. In contrast, the second type, which indicates that the first oxidation step bypasses the aldehyde via an NAD+-dependent bimolecular nucleophilic substitution (SN2) reaction, is consistent with the experimental phenomena, including those that cannot be explained by the first type. This NAD+-dependent SN2 mechanism is thus more reasonable and likely applicable to other oxidoreductases that catalyze four-electron oxidation reactions.

scholarly journals Theoretical study of catalytic mechanism for single-site water oxidation process

2012 ◽  
Vol 109 (39) ◽  
pp. 15669-15672 ◽  
Author(s):  
X. Lin ◽  
X. Hu ◽  
J. J. Concepcion ◽  
Z. Chen ◽  
S. Liu ◽  
...  
Keyword(s):  
Water Oxidation ◽  
Catalytic Mechanism ◽  
Theoretical Study ◽  
Oxidation Process ◽  
Single Site ◽  
Site Water
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