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In chemistry, an electrophile is a chemical species that forms bonds with nucleophiles by accepting an electron pair. [1] Because electrophiles accept electrons, they are Lewis acids . [ 2 ] Most electrophiles are positively charged , have an atom that carries a partial positive charge, or have an atom that does not have an octet of electrons.
Electrophilicity refers to the tendency of an electron-deficient species, called an electrophile, to accept electrons. [28] Similarly, nucleophilicity is defined as the affinity of an electron-rich species, known as a nucleophile, to donate electrons to another species. [ 29 ]
An example of a substitution reaction taking place by a so-called borderline mechanism as originally studied by Hughes and Ingold [6] is the reaction of 1-phenylethyl chloride with sodium methoxide in methanol. The reaction rate is found to the sum of S N 1 and S N 2 components with 61% (3,5 M, 70 °C) taking place by the latter.
Vicinal difunctionalization refers to a chemical reaction involving transformations at two adjacent centers (most commonly carbons). This transformation can be accomplished in α,β-unsaturated carbonyl compounds via the conjugate addition of a nucleophile to the β-position followed by trapping of the resulting enolate with an electrophile at the α-position.
A nitrogen bound to both a good electrofuge and a good nucleofuge is known as a nitrenoid (for its resemblance to a nitrene). [2] Nitrenes lack a full octet of electrons are thus highly electrophilic; nitrenoids exhibit analogous behavior and are often good substrates for electrophilic amination reactions.
The overall reaction for electrophilic addition to ethylene.. In organic chemistry, an electrophilic addition (A E) reaction is an addition reaction where a chemical compound containing a double or triple bond has a π bond broken, with the formation of two new σ bonds.
In general, in a group across the periodic table, the more basic the ion (the higher the pK a of the conjugate acid) the more reactive it is as a nucleophile. Within a series of nucleophiles with the same attacking element (e.g. oxygen), the order of nucleophilicity will follow basicity.
For example, compared to benzene, pyrrole is more rapidly attacked by electrophiles. Pyrrole is therefore considered to be an electron-rich aromatic ring. [ 5 ] Similarly, benzene derivatives with electron-donating groups (EDGs) are attacked by electrophiles faster than in benzene. [ 6 ]