Concept

Effet mésomère

Publications associées (21)

Metal-bearing and trifluoromethyl-substituted pyrimidines: generation and functionalization

5-Pyrimidyllithium species are fairly stable when the metal is flanked by two electron-withdrawing substituents such as trifluoromethyl and chlorine or bromine. Thus, the corresponding 5-carboxylic acids are produced in high yields from 4,5-dibromo-6-(trif ...

2006

The reactivity of 2-fluoro- and 2-chloropyridines toward sodium ethoxide: Factors governing the rates of nucleophilic (het)aromatic substitutions

Thierry Rausis

The relative displacement rates of the halide substituent from 2-fluoro- and 2-chloropyridines by EtONa in EtOH at +25 Deg were assessed by competition kinetics. The 2-fluoropyridine reacts 320 times faster than the chloro analog. A CF3 group increases the ...

2005

Fluorine in an heteroaromatic context

Thierry Rausis

The organometallic approach to the functionalization of arenes and heteroarenes has recently been investigated by our group introducing modifications of the standard methods. This includes, in particular, the basicity-driven heavy halogen migration, which ...

EPFL2005

The organometallic approach to the functionalization of five- and six-membered nitrogen heterocycles

Levente Ondi

The present thesis work concerns the preparation and optionally site selective functionalization of five- and six-membered nitrogen heterocycles and the investigation of atropisomerism of α,o-bis(methoxymethyl)-1-phenylindole. Mono- and disubstituted 2-bro ...

EPFL2005

New insight into the chemistry of allymetals

Eric Masson

The present thesis work provides new insight into the generation of allylmetal species and into their reactivity toward electrophiles. endo-Allylpotassiums are known to be more stable than their corresponding exo-isomers. The ring strain of methylenecycloa ...

EPFL2005

Development and application of a decomposition methodology for interpretation of reactivity effect discrepancies

Rakesh Chawla, Filippo Tani, Fabian Jatuff

With reactivity being the most important integral reactor physics quantity - and simultaneously the one that can be measured with the highest accuracy there is a great interest in understanding how possible space- and energy-dependent data and/or modeling ...

ANS2004

Structural properties and photoreactivity relationships of substituted phenols in TiO2 suspensions

César Pulgarin, Sandra Parra Cardona

The reactivity of phenolic compounds can be drastically affected by the electronic nature of substituents and by their positions in the aromatic ring. In this work, structure effect on the photoreactivity via TiO2 catalysis is studied using several substit ...

2003

Stereoselective synthesis of new 8-oxabicyclo[3.2.1]oct-6-en-2-one and 8-oxabicyclo[3.2.1]octa-3,6-dien-2-one derivatives. The electron-releasing and electron-withdrawing effects of homoconjugated ketones

Pierre Vogel

Two successive brominations of 8-oxabicyclo[3.2.1]oct-6-en-2-one 6 provided 3-exo,6-exo,7-endo-tribromo-7oxabicyclo[3.2.1]octan-2-endo-one 10 with high stereoselectivity. NaBH4 reduced 10 into 3-exo, 6-exo,7-endo-tribromo-8-oxabicyclo[3.2.1]octan-2-endo-ol ...

2001

Coupling of photocatalytic and biological processes as a contribution to the detoxification of water

Sandra Parra Cardona

This research contributes to the study and development of a new degradation technique that couples solar and biological processes for the treatment of biorecalcitrant, nonbiodegradable, and/or toxic organic substances present in the aqueous medium. Efficie ...

EPFL2001

Switching on and off metalation sites in triarylphosphines by manipulating substrate coordination

The inductive electron-withdrawing effect of the pos. charged P atom in triarylphosphine-BH3 adducts is largely compensated by the steric congestion caused in its vicinity. Therefore, Ph3P.BH3 reacts only sluggishly even with superbasic reagents, and produ ...

1998

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