Aryl radical
An Aryl radical in organic chemistry
Organic chemistry
Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, composition, reactions, and preparation of carbon-based compounds, hydrocarbons, and their derivatives...

 is an reactive intermediate
Reactive intermediate
In chemistry a reactive intermediate is a short-lived, high energy, highly reactive molecule. When generated in a chemical reaction it will quickly convert into a more stable molecule. Only in exceptional cases can these compounds be isolated and stored, e.g. low temperatures, matrix isolation...

 and an arene compound incorporating one free radical 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 a 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, photochemical reactions and redox reactions. In organic synthesis,...



Aryl radicals can be obtained via aryl diazonium salts. Alternatives for these salts are certain aryl triazene
Triazene, also known as triazanylene, is an unsaturated inorganic compound having the chemical formula N3H3. It has one double bond, and is the second simplest member of the azene class of hydronitrogen compounds, and is not found in nature. It is also the name given to the functional group...

s and aryl hydrazine
Hydrazine is an inorganic compound with the formula N2H4. It is a colourless flammable liquid with an ammonia-like odor. Hydrazine is highly toxic and dangerously unstable unless handled in solution. Approximately 260,000 tons are manufactured annually...

s. Aryl bromides and iodides can be converted to aryl radicals via tributyltin hydride
Tributyltin hydride
Tributyltin hydride is an organotin compound with the formula 3SnH. It is a colorless liquid that is soluble in organic solvents. The compound is used as a source of hydrogen atoms in organic synthesis.-Synthesis and characterization:...

 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, and an...

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

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


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.


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 term for a variety of reactions where two hydrocarbon fragments are coupled with the aid of a metal 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....

  • addition to iminium ions
  • addition to sulfur dioxide
    Sulfur dioxide
    Sulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...

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