Search results
Results from the WOW.Com Content Network
In chemistry, a nucleophilic substitution (S N) is a class of chemical reactions in which an electron-rich chemical species (known as a nucleophile) replaces a functional group within another electron-deficient molecule (known as the electrophile). The molecule that contains the electrophile and the leaving functional group is called the ...
For example, in the S N 2 mechanism, a nucleophile attacks an organic compound containing the nucleofuge (the bromo group) which simultaneously breaks the bond with the nucleofuge. SN2 reaction of bromoethane with hydroxide ion
A hydroxide ion acting as a nucleophile in an S N 2 reaction, converting a haloalkane into an alcohol. In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they ...
The general mechanism for methyl transfer is a S N 2-like nucleophilic attack where the methionine sulfur serves as the leaving group and the methyl group attached to it acts as the electrophile that transfers the methyl group to the enzyme substrate.
Nucleophile strength is also affected by charge and electronegativity: nucleophilicity increases with increasing negative charge and decreasing electronegativity. For example, OH − is a better nucleophile than water, and I − is a better nucleophile than Br − (in polar protic solvents). In a polar aprotic solvent, nucleophilicity increases ...
with regards to nucleophilic substitution reactions, electron-rich species are relatively strong nucleophiles, as judged by rates of attack by electrophiles. For example, compared to benzene , pyrrole is more rapidly attacked by electrophiles.
Therefore, the nucleophile attacks the more substituted carbon because it retains a more positive character than the lesser substituted carbon. Stereochemically, oxymercuration is an anti addition. As illustrated by the second step, the nucleophile cannot attack the carbon from the same face as the mercury ion because of steric hindrance.
The leaving group is denoted "X", and the nucleophile is denoted "Nu–H". The unimolecular nucleophilic substitution ( S N 1 ) reaction is a substitution reaction in organic chemistry . The Hughes-Ingold symbol of the mechanism expresses two properties—"S N " stands for " nucleophilic substitution ", and the "1" says that the rate ...