Electrophilic substitution
- Electrophilic substitution
Electrophilic substitution reactions are chemical reactions in which an electrophile displaces another group, typically but not always hydrogen. Electrophilic substitution is characteristic of aromatic compounds. Electrophilic aromatic substitution is an important way of introducing functional groups on benzene rings. The other main reaction type is electrophilic aliphatic substitution.
Electrophilic aromatic substitution
The most important reactions of this type that take place are aromatic nitration, aromatic halogenation, aromatic sulfonation and acylation and alkylating Friedel-Crafts reactions.
Electrophilic aliphatic substitution
In electrophilic substitution in aliphatic compounds, an electrophile displaces a functional group. This reaction is similar to nucleophilic aliphatic substitution where the reactant is a nucleophile rather than an electrophile. The two electrophilic reaction mechanisms, SE1 and SE2 (Substitution Electrophilic), are also similar to the nucleophile counterparts SN1 and SN2. In the SE1 course of action the substrate first ionizes into a carbanion and a positively charged organic residue. The carbanion then quickly recombines with the electrophile. The SE2 reaction mechanism has a single transition state in which the old bond and the newly formed bond are both present.
Electrophilic aliphatic substitution reactions are:
* Nitrosation
* Ketone halogenation
* Keto-enol tautomerism
* aliphatic diazonium coupling
* carbene insertion into C-H bonds
See also
* Nucleophilic substitution
References
*cite book|first=Jerry|last=March|title=Advanced Organic Chemistry|edition=5th ed|publisher=Wiley|year=1985
Wikimedia Foundation.
2010.
Look at other dictionaries:
electrophilic substitution — noun in aromatic organic chemistry, a form of substitution reaction in which the leaving functional group (normally hydrogen) is replaced with an electrophile … Wiktionary
Electrophilic aromatic substitution — or EAS is an organic reaction in which an atom, usually hydrogen, appended to an aromatic system is replaced by an electrophile. The most important reactions of this type that take place are aromatic nitration, aromatic halogenation, aromatic… … Wikipedia
Substitution reaction — In a substitution reaction, a functional group in a particular chemical compound is replaced by another group.[1][2] In organic chemistry, the electrophilic and nucleophilic substitution reactions are of prime importance. Organic substitution… … Wikipedia
substitution reaction — Chem. the replacement of an atom or group of atoms in a compound by another atom or group. * * * ▪ chemical reaction any of a class of chemical reactions in which an atom, ion, or group of atoms or ions in a molecule is replaced by another… … Universalium
Substitution électrophile — La substitution électrophile (SE) est une réaction organique de type substitution dans laquelle un électrophile remplace un autre groupe, la plupart du temps un atome d hydrogène, sur un composé chimique. Son nom suggère que c est un type de… … Wikipédia en Français
substitution reaction — noun a reaction in which one functional group is replaced with another See Also: nucleophilic substitution, electrophilic substitution … Wiktionary
Electrophilic halogenation — In organic chemistry, an electrophilic aromatic halogenation is a type of electrophilic aromatic substitution. This organic reaction is typical of aromatic compounds and a very useful method for adding substituents to an aromatic system.:A few… … Wikipedia
Electrophilic addition — In organic chemistry, an electrophilic addition reaction is an addition reaction where, in a chemical compound, a pi bond is removed by the creation of two new covalent bonds. In Electrophilic addition reactions, common substrates have a carbon… … Wikipedia
Arene substitution patterns — are part of organic chemistry IUPAC nomenclature and pinpoint the position of substituents other than hydrogen in relation to each other on an aromatic hydrocarbon. Contents 1 Ortho, meta, and para substitution 2 Ipso, meso, and peri substitution … Wikipedia
Nucleophilic substitution — In organic and inorganic chemistry, nucleophilic substitution is a fundamental class of reactions in which an electron nucleophile selectively bonds with or attacks the positive or partially positive charge of an atom or a group of atoms called… … Wikipedia
