نتایج جستجو برای: nucleophilicity

تعداد نتایج: 348  

Journal: :Chemical communications 2005
Christopher A Reed

Icosahedral carborane anions such as CHB11Cl11- are amongst the least coordinating, most chemically inert anions known. They are also amongst the least basic, so their conjugate acids, H(carborane), are superacids (i.e. stronger than 100% H2SO4). Acidity scale measurements indicate that H(CHB11Cl11) is the strongest pure Brønsted acid presently known, surpassing triflic and fluorosulfuric acid....

2016
Jun Yuan Tingting Sun Xin He Ke An Jun Zhu Liang Zhao

Polymetalated aromatic compounds are particularly challenging synthetic goals because of the limited thermodynamic stability of polyanionic species arising from strong electrostatic repulsion between adjacent carbanionic sites. Here we describe a facile synthesis of two polyaurated complexes including a tetra-aurated indole and an octa-aurated benzodipyrrole. The imido trinuclear gold(I) moiety...

Journal: :Yakugaku zasshi : Journal of the Pharmaceutical Society of Japan 2004
Tatsushi Imahori

A novel type of deprotonative functionalization of aromatics was accomplished with a phosphazene base (t-Bu-P4 base). For various nitrogen heteroaromatics and benzene derivatives, deprotonative 1,2-additions proceeded with the t-Bu-P4 base and ZnI(2) as an additive in the presence of carbonyl compounds. The t-Bu-P4 base has both extremely strong Brønsted basicity and less nucleophilicity due to...

Journal: :International Journal of Molecular Sciences 2008
Malcolm J. D’Souza Lamia Yaakoubd Stacey L. Mlynarski Dennis N. Kevill

Specific rates of solvolysis in hydroxylic solvents available for the solvolysis of 2-thiophenesulfonyl chloride and phenylmethanesulfonyl chloride are supplemented by determining the values in fluoroalcohol-containing solvents. The data sets are then correlated using the extended Grunwald-Winstein equation. For both substrates, it is found that a single correlation controls the influence of so...

Journal: :Dalton transactions 2015
Priyam Bharadwaz Bitupon Borthakur Ashwini K Phukan

Theoretical calculations were carried out to understand the effect of annulation on the electronic and ligand properties of boron substituted N-heterocyclic carbenes (B-NHCs). Annulation results in a decrease in stability as indicated by the calculated values of singlet-triplet separations and stabilization energies as well as HOMO-LUMO gaps. Annulated B-NHCs are found to be weaker σ-donors but...

Journal: :Angewandte Chemie 2016
Benjamin Schumann Sharavathi G Parameswarappa Marilda P Lisboa Naresh Kottari Fabio Guidetti Claney L Pereira Peter H Seeberger

The glycosylation reaction is the key transformation in oligosaccharide synthesis, but it is still difficult to control in many cases. Stereocontrol during cis-glycosidic linkage formation relies almost exclusively on tuning the glycosylating agent or the reaction conditions. Herein, we use nucleophile-directed stereocontrol to manipulate the stereoselectivity of glycosylation reactions. Placin...

Journal: :Dalton transactions 2013
Federica Zaccheria Nicola Scotti Marcello Marelli Rinaldo Psaro Nicoletta Ravasio

There is a renewed interest in designing solid acid catalysts particularly due to the significance of Lewis acid catalyzed processes such as Friedel-Crafts acylation and alkylation and cellulose hydrolysis for the development of sustainable chemistry. This paper reports a new focus point on the properties of supported CuO on silica, a material that up to now has been considered only as the prec...

Journal: :Carbohydrate Research 2021

In this paper, the synthesis of different bisglucosides is investigated through reaction two acetylated glucose units with a diol (or diphenol) in order to develop versatile molecular platform for future development bio-based polymers. A panel five diols and one diphenol initially used examine influence their chemical skeleton on yield both nature proportion formed species. Reaction products ar...

2016
Dmitry S Ryabukhin Dmitry N Zakusilo Mikhail O Kompanets Anton A.Tarakanov Irina A Boyarskaya Tatiana O Artamonova Mikhail A Khohodorkovskiy Iosyp O Opeida Aleksander V Vasilyev

The reaction of 5-hydroxymethylfurfural (5-HMF) with arenes in superacidic trifluoromethanesulfonic acid (triflic acid, TfOH) as the solvent at room temperature for 1-24 h gives rise to 5-arylmethylfurfurals (yields of 17-91%) and 2-arylmethyl-5-(diarylmethyl)furans (yields of 10-37%). The formation of these two types of reaction products depends on the nucleophilicity of the arene. The same re...

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