نتایج جستجو برای: nucleophilicity

تعداد نتایج: 348  

Journal: :Organic & biomolecular chemistry 2010
Christiane E I Knappke Jörg M Neudörfl Axel Jacobi von Wangelin

A series of novel 2-alkylidene imidazolines has been synthesized from imidazolium halides and substituted alkyl halides in the presence of base. The resultant exocyclic enediamines have been characterized and their nucleophilicity has been evaluated upon NMR spectroscopic data and substitution reactions.

Journal: :Chemical communications 2015
J Marchois C Fressigné B Lecachey J Maddaluno

The competition between basicity and nucleophilicity of two standard organolithium reagents was studied using DFT. Comparing the reactivity of solvated (MeLi)2 and (LDA)2 toward propanal finally explains why methyllithium adds onto the carbonyl while LDA deprotonates the α-position, in accord with experiment and Ireland's deprotonation TS.

2014
Paul Moody Vijay Chudasama Ramiz I. Nathani Antoine Maruani Stephen Martin Mark E. B. Smith Stephen Caddick

Designed ankyrin repeat proteins (DARPins) are valuable tools in both biochemistry and medicine. Herein we describe a rapid, simple method for the dual modification of DARPins by introduction of cysteine mutations at specific positions that results in a vast difference in their thiol nucleophilicity, allowing for clean sequential modification.

Journal: :Chemical communications 2014
Maciej Stodulski Alissa Goetzinger Stefanie V Kohlhepp Tanja Gulder

The nucleophilicity of the substituents in iodobenzene pre-catalysts have a huge impact on product selectivity in iodine(III) triggered halogenations, steering the reactivity from solely carbocyclizations towards dihalogenations. Utilizing this catalyst-dependent reactivity a diastereo- and chemoselective dihalogenation method was established allowing the conversion of structurally and electron...

1998
Robert J. Pafford Thomas B. Rauchfuss

The pentacoordinate complex ZnS4(PMDETA) (1) is formed by treatment of ZnS6(TMEDA) (2) with the tridentate ligand pentamethyldiethylenetriamine (PMDETA). 1H NMR studies show that samples of 1 react with elemental sulfur to produce a significant (<30%) amount of a second polysulfido complex, assigned as ZnS5(PMDETA). Crystallographic studies reveal that 1 has a ZnN3S2 coordination sphere with a ...

2016
Chung-Min Park Brett A. Johnson Jicheng Duan Jeong-Jin Park Jacob J. Day David Gang Wei-Jun Qian Ming Xian

The development of a functional disulfide, FmSSPy-A (Fm = 9-fluorenylmethyl; Py = pyridinyl), is reported. It can effectively convert small molecule and protein thiols (-SH) to form -S-SFm adducts under mild conditions. This method allows for a H2S-free and biomimetic protocol to generate highly reactive persulfides (in their anionic forms). The high nucleophilicity of persulfides toward a numb...

Journal: :Journal of the Turkish Chemical Society, Section A: Chemistry 2016

2001
W. J. Baron M. E. Hendrick

First-order rate coefficients have been obtained for the solvolysis of triethyloxonium hexafluorophosphate in a variety of organic and aqueous-organic solvents. These have been used to set up a scale of solvent nucleophilicities based upon the four-parameter (two-term) Grunwald-Winstein equation. The required corrections for variation in solvent influence upon the leaving group were estimated f...

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