Aryl radical

An Aryl radical in organic chemistry

Organic chemistry

Organic chemistry is a discipline within chemistry which involves the scientific study of the structure, properties, composition, reactions, and preparation of chemical compounds that contain carbon...

 is an reactive intermediate and an arene compound incorporating one free radical carbon

Carbon

Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...

 atom as part of the ring structure. As such it is the radical counterpart of the Arenium ion

Arenium ion

An arenium ion in organic chemistry is the cyclohexadienyl cation that appears as a reactive intermediate in electrophilic aromatic substitution. For historic reasons this complex is also called a Wheland intermediate or a sigma complex or σ-complex.Two hydrogen atoms bonded to one carbon lie in a...

. The parent compound is the phenyl radical C₆H₅^. . Aryl radicals are intermediates in certain organic reaction

Organic reaction

Organic reactions are chemical reactions involving organic compounds. The basic organic chemistry reaction types are addition reactions, elimination reactions, substitution reactions, pericyclic reactions, rearrangement reactions and redox reactions. In organic synthesis, organic reactions are used...

s.


Aryl radicals can be obtained via aryl diazonium salts.

An Aryl radical in organic chemistry

Organic chemistry

Organic chemistry is a discipline within chemistry which involves the scientific study of the structure, properties, composition, reactions, and preparation of chemical compounds that contain carbon...

 is an reactive intermediate and an arene compound incorporating one free radical carbon

Carbon

Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...

 atom as part of the ring structure. As such it is the radical counterpart of the Arenium ion

Arenium ion

An arenium ion in organic chemistry is the cyclohexadienyl cation that appears as a reactive intermediate in electrophilic aromatic substitution. For historic reasons this complex is also called a Wheland intermediate or a sigma complex or σ-complex.Two hydrogen atoms bonded to one carbon lie in a...

. The parent compound is the phenyl radical C₆H₅^. . Aryl radicals are intermediates in certain organic reaction

Organic reaction

Organic reactions are chemical reactions involving organic compounds. The basic organic chemistry reaction types are addition reactions, elimination reactions, substitution reactions, pericyclic reactions, rearrangement reactions and redox reactions. In organic synthesis, organic reactions are used...

s.

Synthesis

Aryl radicals can be obtained via aryl diazonium salts. Alternatives for these salts are certain aryl triazene

Triazene

Triazene is the chemical compound NH₂N=NH but it has also given name to the functional group consisting of an amine directly bonding to an azo group, i.e. with the linkage R2N-N=NR' where R and R' are substituents...

s and aryl hydrazine

Hydrazine

Hydrazine is an inorganic chemical compound with the formula N₂H₄. It is a colourless liquid with an ammonia-like odor and is derived from the same industrial chemistry processes that manufacture ammonia...

s. Aryl bromides and iodides can be converted to aryl radicals via tributyltin hydride

Tributyltin hydride

Tributyltin hydride is an organotin compound. It is a useful reagent in organic synthesis. Combined with azobisisobutyronitrile or by irradiation with light, tributyltin hydride cleaves to form the tributyltin radical , which reacts with substrate by substitution of a halogen atom for a hydrogen...

 and related compounds and silyl hydride

Silyl hydride

Silicon hydrides are chemical compounds which contain a silicon-hydrogen bond. The silicon to hydrogen bond is longer than the C–H bond and weaker . Hydrogen is more electronegative than silicon hence the naming convention of silyl hydrides. The parent compound SiH₄ is called silane,...

s. Aryl halides can also be converted via electrochemical cathodic reduction

Electrosynthesis

Electrosynthesis in organic chemistry is the synthesis of chemical compounds in a electrochemical cell The main advantage of electrosynthesis over an ordinary redox reaction is avoidance of the potential wasteful other half-reaction and the ability to precisely tune the required potential...

The mushroom

Mushroom

A mushroom is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground on soil or on its food source. The standard for the name "mushroom" is the cultivated white button mushroom, Agaricus bisporus, hence the word mushroom is most often applied to those fungi that have...

 Stephanospora caroticolor is suspected to generate an aryl radical as part of its biological chemical defence mechanism.

Spectroscopy

The parent phenyl radical has been identified via electron paramagnetic resonance

Electron paramagnetic resonance

Electron paramagnetic resonance or electron spin resonance spectroscopyis a technique for studying chemical species that have one or more unpaired electrons, such as organic and inorganic free radicals or inorganic complexes possessing a transition metal ion...

 and UV spectroscopy.

Reactions

Aryl radicals are very reactive and are found in many different reactions. Proton abstraction is considered a side reaction. Several reactions of synthetic utility in which aryl radicals feature are:

• Halogen transfer
• reaction with electron-deficient alkenes in the meerwein arylation
  Meerwein arylation
  The Meerwein arylation is an organic reaction involving the addition of an aryl diazonium salt to an electron-poor alkene usually supported by a metal salt. The reaction product is an alkylated arene compound...
  
  
• biaryl couplings
  Coupling reaction
  A coupling reaction in organic chemistry is a catch-all for a range of reactions in organometallic chemistry where two hydrocarbon fragments are coupled with the aid of a metal containing catalyst....
  
  
• Sandmeyer reaction
  Sandmeyer reaction
  The Sandmeyer reaction is a chemical reaction used to synthesize aryl halides from aryl diazonium salts. It is named after the Swiss chemist Traugott Sandmeyer....
  
  s
• addition to iminium ions
• addition to sulfur dioxide
  Sulfur dioxide
  Sulfur dioxide is the chemical compound with the formula SO₂. It is produced by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide...