Editing Phenyl group (section)

==Preparation, occurrence, and applications==
Phenyl groups are usually introduced using reagents that behave as sources of the phenyl anion or the phenyl cation. Representative reagents include [[phenyllithium]] ({{chem2|C6H5Li}}) and [[phenylmagnesium bromide]] ({{chem2|C6H5MgBr}}). Electrophiles are attacked by benzene to give phenyl derivatives:
:<chem>C6H6 + E+ -> C6H5E + H+</chem>
where {{chem2|E+}} (the "electrophile") = {{chem2|Cl+, NO2+, SO3}}. These reactions are called [[electrophilic aromatic substitution]]s.
<gallery caption="Representative compounds containing phenyl groups" widths="180px" heights="120px" perrow="5">
File: Atorvastatin.svg|[[Atorvastatin|Atorvastatin (Lipitor)]], a [[Pharmaceutical drug#Blockbuster drug|blockbuster drug]] featuring two phenyl and one ''p''-fluorophenyl groups. It is used to lower cholesterol in people with [[hypercholesterolaemia]].
File: Fexofenadine2DCSD.svg|[[Fexofenadine|Fexofenadine (Allegra, Telfast)]], another blockbuster drug, which features a diphenylmethyl group as well as a ''p''-[[phenylene]] ({{chem2|C6H4}}) group. It is an [[antihistamine]] used to treat [[allergies]].
File: Phenylalanin_-_Phenylalanine.svg|[[Phenylalanine]], a common amino acid.
File: Bifenyl.svg|[[Biphenyl]], consisting of two phenyl groups. The two rings tend not to be coplanar.
File: Chlorobenzene2.svg|[[Chlorobenzene]] (or phenyl chloride), a solvent.
</gallery>

Phenyl groups are found in many organic compounds, both natural and synthetic (see figure). Most common among natural products is the [[amino acid]] [[phenylalanine]], which contains a phenyl group. A major product of the [[petrochemical industry]] is "[[Benzene#Production|BTX]]" consisting of benzene, toluene, and xylene - all of which are building blocks for phenyl compounds. The [[polymer]] [[polystyrene]] is derived from a phenyl-containing monomer and owes its properties to the rigidity and hydrophobicity of the phenyl groups. Many drugs as well as many pollutants contain phenyl rings.
One of the simplest phenyl-containing compounds is [[phenol]], {{chem2|C6H5OH}}. It is often said the [[resonance (chemistry)|resonance stability]] of phenol makes it a stronger [[acid]] than that of [[aliphatic]] [[alcohols]] such as [[ethanol]] ([[acid dissociation constant|p''K''<sub>a</sub>]] = 10 vs. 16–18). However, a significant contribution is the greater [[electronegativity]] of the ''sp''<sup>2</sup> [[alpha carbon]] in phenol compared to the ''sp''<sup>3</sup> alpha carbon in aliphatic alcohols.<ref name="Silva2009">{{cite journal|last1=Silva|first1=Pedro Jorge|title=Inductive and Resonance Effects on the Acidities of Phenol, Enols, and Carbonyl α-Hydrogens|journal=The Journal of Organic Chemistry|volume=74|issue=2|year=2009|pages=914–916|issn=0022-3263|doi=10.1021/jo8018736|pmid=19053615|hdl=10284/3294|hdl-access=free}}</ref>