scholarly journals Uncatalyzed conjugate addition of organozinc halides to enones in DME: a combined experimental/computational study on the role of the solvent and the reaction mechanism

2020 ◽  
Vol 11 (1) ◽  
pp. 257-263 ◽  
Author(s):  
Gianluca Casotti ◽  
Gianluca Ciancaleoni ◽  
Filippo Lipparini ◽  
Chiara Nieri ◽  
Anna Iuliano

The reaction mechanism of a new conjugate addition reaction of organozinc halides to enones is disclosed by a combined experimental/computational study.

2016 ◽  
Vol 14 (27) ◽  
pp. 6577-6590 ◽  
Author(s):  
Wei Zhang ◽  
Yang Wang ◽  
Donghui Wei ◽  
Mingsheng Tang ◽  
Xinju Zhu

A computational study on NHC-catalyzed intramolecular aldehyde–ketone crossed-benzoin reaction has been performed using a DFT method.


RSC Advances ◽  
2021 ◽  
Vol 11 (30) ◽  
pp. 18246-18251
Author(s):  
Selçuk Eşsiz

A computational study of metal-free cyanomethylation and cyclization of aryl alkynoates with acetonitrile is carried out employing density functional theory and high-level coupled-cluster methods, such as [CCSD(T)].


Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4746
Author(s):  
An-Ting Tu ◽  
Jer-An Lin ◽  
Chieh-Hsiu Lee ◽  
Yi-An Chen ◽  
Jung-Tsung Wu ◽  
...  

5-Hydroxymethylfurfural (5-HMF) is a harmful substance generated during the processing of black garlic. Our previous research demonstrated that impregnation of black garlic with epigallocatechin gallate (EGCG) could reduce the formation of 5-HMF. However, there is still a lack of relevant research on the mechanism and structural identification of EGCG inhibiting the production of 5-HMF. In this study, an intermediate product of 5-HMF, 3-deoxyglucosone (3-DG), was found to be decreased in black garlic during the aging process, and impregnation with EGCG for 24 h further reduced the formation of 3-DG by approximately 60% in black garlic compared with that in the untreated control. The aging-mimicking reaction system of 3-DG + EGCG was employed to determine whether the reduction of 3-DG was the underlying mechanism of decreased 5-HMF formation in EGCG-treated black garlic. The results showed that EGCG accelerated the decrease of 3-DG and further attenuated 5-HMF formation, which may be caused by an additional reaction with 3-DG, as evidenced by LC-MS/MS analysis. In conclusion, this study provides new insights regarding the role of EGCG in blocking 5-HMF formation.


Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4083
Author(s):  
Heming Jiang ◽  
Tian-Yu Sun

A computational study on the origin of the activating effect for Pd-catalyzed directed C–H activation by the concerted metalation-deprotonation (CMD) mechanism is conducted. DFT calculations indicate that strong acids can make Pd catalysts coordinate with directing groups (DGs) of the substrates more strongly and lower the C–H activation energy barrier. For the CMD mechanism, the electrophilicity of the Pd center and the basicity of the corresponding acid ligand for deprotonating the C–H bond are vital to the overall C–H activation energy barrier. Furthermore, this rule might disclose the role of some additives for C–H activation.


Antioxidants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1024
Author(s):  
Sebastien Dupont ◽  
Paul Fleurat-Lessard ◽  
Richtier Gonçalves Cruz ◽  
Céline Lafarge ◽  
Cédric Grangeteau ◽  
...  

Although the functions and structural roles of sterols have been the subject of numerous studies, the reasons for the diversity of sterols in the different eukaryotic kingdoms remain unclear. It is thought that the specificity of sterols is linked to unidentified supplementary functions that could enable organisms to be better adapted to their environment. Ergosterol is accumulated by late branching fungi that encounter oxidative perturbations in their interfacial habitats. Here, we investigated the antioxidant properties of ergosterol using in vivo, in vitro, and in silico approaches. The results showed that ergosterol is involved in yeast resistance to tert-butyl hydroperoxide and protects lipids against oxidation in liposomes. A computational study based on quantum chemistry revealed that this protection could be related to its antioxidant properties operating through an electron transfer followed by a proton transfer mechanism. This study demonstrates the antioxidant role of ergosterol and proposes knowledge elements to explain the specific accumulation of this sterol in late branching fungi. Ergosterol, as a natural antioxidant molecule, could also play a role in the incompletely understood beneficial effects of some mushrooms on health.


ChemInform ◽  
2005 ◽  
Vol 36 (44) ◽  
Author(s):  
A. Alexakis

ChemInform ◽  
2013 ◽  
Vol 44 (22) ◽  
pp. no-no
Author(s):  
Alyson E. Garst ◽  
Alexandra D. Badiceanu ◽  
Kristine A. Nolin

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