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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 ...
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 ...
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.
With nitrile electrophiles, nucleophilic addition take place by: [1] hydrolysis of a nitrile to form an amide or a carboxylic acid; organozinc nucleophiles in the Blaise reaction; alcohols in the Pinner reaction. the (same) nitrile α-carbon in the Thorpe reaction. The intramolecular version is called the Thorpe–Ziegler reaction.
In the S N 1 reaction the nucleophile attacks after the rate-limiting step is over, whereas in S N 2 the nucleophile forces off the leaving group in the limiting step. In other words, the rate of S N 1 reactions depend only on the concentration of the substrate while the S N 2 reaction rate depends on the concentration of both the substrate and ...
Acyl substitution occurs when a nucleophile attacks a carbon that is doubly bonded to one oxygen and singly bonded to another oxygen (can be N or S or a halogen), called an acyl group. The nucleophile attacks the carbon causing the double bond to break into a single bond. The double can then reform, kicking off the leaving group in the process.
The Williamson ether reaction follows an S N 2 (bimolecular nucleophilic substitution) mechanism. In an S N 2 reaction mechanism there is a backside attack of an electrophile by a nucleophile and it occurs in a concerted mechanism (happens all at once).
Acyl compounds react with nucleophiles via an addition mechanism: the nucleophile attacks the carbonyl carbon, forming a tetrahedral intermediate. This reaction can be accelerated by acidic conditions, which make the carbonyl more electrophilic , or basic conditions, which provide a more anionic and therefore more reactive nucleophile.