scholarly journals Nucleophilic reactivity of the gold atom in a diarylborylgold(i) complex toward polar multiple bonds

2021 ◽  
Author(s):  
Akane Suzuki ◽  
Xueying Guo ◽  
Zhenyang Lin ◽  
Makoto Yamashita

A di(o-tolyl)borylgold complex added to CO/N double bond to form Au–C and B–O/N bonds. DFT calculations revealed a two-step mechanism consisting of the coordination of O/N atom to B atom followed by nucleophilic migration of Au atom.

Tetrahedron ◽  
1966 ◽  
Vol 22 ◽  
pp. 399-420 ◽  
Author(s):  
P.D. Bartlett ◽  
E.M. Nicholson ◽  
R. Owyang

2021 ◽  
Author(s):  
Andrey I Puzanov ◽  
Dmitry S Ryabukhin ◽  
Anna S Zalivatskaya ◽  
Dmitriy N Zakusilo ◽  
Darya S Mikson ◽  
...  

Acetylene derivatives of 1,2,4-oxadiazoles, 5-(2-arylethynyl)-3-aryl-1,2,4-oxadiazoles, have been obtained, for the first time, from 5-(2-arylethenyl)-3-aryl-1,2,4-oxadiazoles by their bromination at the carbon-carbon double bond followed by di-dehydrobromination with NaNH2 in liquid NH3.  Reaction of the acetylene 1,2,4-oxadiazoles with arenes in neat triflic acid TfOH (CF3SO3H) at room temperature for 1 h result in the formation of E-/Z-5-(2,2-diarylethenyl)-3-aryl-1,2,4-oxadiazoles as products of regioselective hydroarylation of the acetylene bond. Addition of TfOH to acetylene bond of these oxadiazoles gives rise quantitatively to E-/Z-vinyl triflates. Reaction cationic intermediates have been studied by DFT calculations. The reaction mechanisms have been discussed.


Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7147
Author(s):  
Katarzyna Mitka ◽  
Katarzyna Fela ◽  
Aleksandra Olszewska ◽  
Radomir Jasiński

The molecular mechanism of the [3 + 2] cycloaddition reaction between C-arylnitrones and perfluoro 2-methylpent-2-ene was explored on the basis of DFT calculations. It was found that despite the polar nature of the intermolecular interactions, as well as the presence of fluorine atoms near the reaction centers, all reactions considered cycloaddition proceed via a one-step mechanism. All attempts for the localization of zwitterionic intermediates on the reaction paths were not successful. Similar results were obtained regardless of the level of theory applied.


2021 ◽  
Author(s):  
Liliang Wang ◽  
Guorong Zhen ◽  
Yinhuan Li ◽  
Mitsuo Kira ◽  
Liping Yan ◽  
...  

Abstract Digoldgermanes with a gold coordinated by a dialkylgermylene ligand, R’2Ge(AuPR3)(AuGeR’2) (3a; R = Me, 3b; R = Et), were synthesized as green solids through the reactions of stable dialkylgermylene 1 with R3PAuCl followed by the reduction with KC8 at ambient temperatures. The structural characteristics of 3a and 3b were elucidated using NMR spectroscopy, X-ray crystallography, and DFT calculations. An intense absorption maximum was observed at 590 nm in the UV-vis spectrum of 3a in hexane. A pendular motion of AuPR3 group between Ge(IV) and Ge(II) of 3a and 3b occurring in the NMR time scale was found by the dynamic 1H NMR analysis, suggesting that the Ge(II) ligand has an enhanced electrophilicity to be attacked by the nucleophilic gold atom which closes to ‒1 oxidation state. DFT calculations of 3a revealed the existence of high-lying σ(Ge-Au) type HOMO and low-lying LUMO with germylene pπ nature. We show the bond formation and activation alternatively at Au or Ge atom, a methylation of digoldgermane 3a with MeOTf affords methylgermane 5. Moreover, the digoldgermane 3a reacts with Cl− ion of Ph4PCl and CH3C(O)Cl smoothly to form the corresponding chloride-addition product 7 and chlorogoldgermane 9, respectively. Cyclic trimerization reactions of aromatic isocyanates were high-efficiently catalyzed by 3a giving the corresponding 1,3,5-triaryl isocyanurates.


2021 ◽  
Vol 22 (24) ◽  
pp. 13460
Author(s):  
Elena Chugunova ◽  
Nurgali Akylbekov ◽  
Alexey Dobrynin ◽  
Alexander Burilov ◽  
Carla Boga ◽  
...  

This research focuses on the X-ray structure of 4,6-dichloro-5-nitrobenzofuroxan 1 and of some of its amino derivatives (4a, 4e, 4g, and 4l) and on DFT calculations concerning the nucleophilic reactivity of 1. We have found that by changing the solvent used for crystallization, it is possible to obtain 4,6-dichloro-5-nitrobenzofuroxan (1) in different polymorphic structures. Moreover, the different torsional angles observed for the nitro group in 1 and in its amino derivatives (4a, 4e, 4g, and 4l) are strictly dependent on the steric hindrance of the substituent at C-4. DFT calculations on the course of the nucleophilic substitution confirm the role of the condensed furoxan ring in altering the aromaticity of the carbocyclic frame, while chlorine atoms strongly influence the dihedral angle and the rotational barrier of the nitro group. These results corroborate previous observations based on experimental kinetic data and give a deep picture of the reaction with amines, which proceeds via a “non-aromatic” nucleophilic substitution.


2015 ◽  
Vol 44 (39) ◽  
pp. 17045-17053 ◽  
Author(s):  
Cong-Zhi Wang ◽  
John K. Gibson ◽  
Jian-Hui Lan ◽  
Qun-Yan Wu ◽  
Yu-Liang Zhao ◽  
...  

Density Functional Theory (DFT) calculations on the actinide dimetallocenes An2Cp*2 (Cp* = C5(CH3)5, An = Th–Pu) reveal the nature of actinide–actinide multiple bonding in these species.


1983 ◽  
Vol 61 (3) ◽  
pp. 533-540 ◽  
Author(s):  
Stanislas Czernecki ◽  
Veronique Dechavanne

The arylation of peracetylated glycals catalyzed by palladium salts provides a new synthesis of C-glycosides. The title reaction is applied to several aromatic compounds, including fluoro and nitro derivatives. The regioselectivity of the reaction with respect to the aromatic nucleus is explained by the formation of an arylpalladium directly from the aromatic compound and the salt. A two-step mechanism, involving syn-addition of the arylpalladium to the glycal double bond, followed by a syn-elimination is proposed and discussed.


2014 ◽  
Vol 69 (5) ◽  
pp. 580-588 ◽  
Author(s):  
Dominic Schmid ◽  
Alexander Seyboldt ◽  
Doris Kunz

Upon reaction of the dipyrido-anellated guanidinium salt 1 with one equivalent of CpNa we were able to synthesize the dipyrido-anellated diaminofulvalene 4 in one step in 33% isolated yield. This shortens the initial route that applies a literature-known fulvalene synthesis via uronium salt 3 by two steps and avoids the need for a sacrificial equivalent of CpNa. Although the X-ray structure analysis reveals a shorter exocyclic double bond than observed in the diaminofulvalene V, a theoretical analysis based upon DFT calculations shows a stronger zwitterionic character for the dipyridofulvalene 4.


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