نتایج جستجو برای: nucleophilicity

تعداد نتایج: 348  

Journal: :Journal of Physical Organic Chemistry 2023

The reference electrophilicity and nucleophilicity scales established at the B3LYP/6-31G(d) level are herein extended by least squares regressions to most common DFT computational methods used in theoretical organic chemistry studies, including B3LYP, MPWB1K, M062-X, ωB97x-D, combination with basis sets of type 6-31G 6-311G different degrees polarization diffuse functions. Excellent linear corr...

2012
Shinjiro Kobayashi Qin Qin Zhu Wolfram Schnabel

Vinyl cations I+, of the structure R^C^CR" (I+: R' = R" = anisyl; R' = phenyl.R" = anisyl. I*: R' — methyl.R" = anisyl) were generated by flash photolysis of corresponding bromides. Lifetime measurements yielded the following: substitution of aromatic groups in 2-position by methyl groups largely improved the electrophilicity of the vinyl cations. The nucleophilicity of typical compounds (keton...

Journal: :Organic & biomolecular chemistry 2015
Naohiko Ikuma Koichi Fujioka Yusuke Misawa Ken Kokubo Takumi Oshima

Oxidation of azafulleroids with peracids regenerated C60 depending on the N-substituents. Alkyl-substituted azafulleroids preferred the oxidation of nitrogen to afford N-oxides as possible intermediates for C60 in moderate yields. Phenyl- and tosyl-substituted azafulleroids rather allowed the oxidation at the carbon cage. Theoretical calculations predicted the order of reactivity of azafulleroi...

Journal: :European Journal of Organic Chemistry 2022

We report the direct incorporation of hexafluoroisobutyl group on a chiral glycine Schiff base complex mediated by 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). The fluoroalkylation involves 2-(bromomethyl)-1,1,1,3,3,3-hexafluoropropane reagent, which generates in situ hexafluoroisobutylene (HFIB), and reacts then with enolate through tandem allylic shift/hydrofluorination process. showed that use ...

Journal: :Organic & biomolecular chemistry 2013
Doris Lee Mark S Taylor

The combination of a boronic acid and a Lewis base, both employed in substoichiometric amounts, enables the regioselective silylation of cis-diol groups in alkylpyranoside substrates. The proposed mode of activation involves the formation of a tetracoordinate adduct that displays enhanced nucleophilicity at the boron-bound alkoxide groups.

Journal: :Molbank 2023

Copper methoxide compound IPrCuOMe was unexpectedly formed in a reaction of IPrCuPPh2 with methyl acrylate. The alkoxide product identified from the mixture spectroscopically and structurally characterized. This C–O bond cleavage likely depends on nucleophilicity Cu–P IPrCuPPh2.

Journal: :Chemical communications 2013
Rosmara Mansueto Valentina Mallardo Filippo Maria Perna Antonio Salomone Vito Capriati

Cycloreversion of α-lithiated phenyltetrahydrofuran was successfully tamed at -78 °C in a non-coordinating solvent in the presence of TMEDA. This anion showed excellent nucleophilicity and could be intercepted with a variety of structurally different electrophiles to give 2,2-disubstituted derivatives which can be further elaborated to γ-butyrolactones.

2005
AKHILESH TANWAR

The size-dependence of different local reactivity descriptors of dimer A2 and AB type of systems is discussed. We derive analytic results of these descriptors calculated using finite difference approximation. In particular, we studied Fukui functions, relative electrophilicity and relative nucleophilicity, local softness and local philicity. The results are explained using the example of the di...

Journal: :Organic & biomolecular chemistry 2012
Amit Sachdeva Scott K Silverman

During in vitro selection for DNA-catalyzed lysine reactivity, we identified a deoxyribozyme that instead catalyzes nucleophilic attack of a phosphoramidate functional group at a 5'-triphosphate-RNA, forming an unusual pyrophosphoramidate (N-P(V)-O-P(V)) linkage. This finding highlights the relatively poor nucleophilicity of nitrogen using nucleic acid catalysts, indicating a major challenge fo...

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