{{Short description|1=Organosulfur compound of the form >S(=O)2}} thumb|150px|right|The structure of a sulfone [[File:Dimethylsulfone-3D-vdW.png|thumb|Dimethyl sulfone, an example of a sulfone]]

In organic chemistry, a '''sulfone''' is a organosulfur compound containing a sulfonyl ({{chem2|R\sS(\dO)2\sR'}}) functional group attached to two carbon atoms. The central hexavalent sulfur atom is double-bonded to each of two oxygen atoms{{dubious|date=July 2025}} and has a single bond to each of two carbon atoms, usually in two separate hydrocarbon substituents.<ref name="ISBN 9780534389512">{{cite book | last = Hornback | first = Joseph | title = Organic Chemistry | publisher = Thomson Brooks/Cole | location = Australia | year = 2006 | isbn = 978-0-534-38951-2}}</ref>

==Synthesis and reactions== ===By oxidation of thioethers and sulfoxides=== Sulfones are typically prepared by organic oxidation of thioethers, often referred to as sulfides. Sulfoxides are intermediates in this route.<ref>{{cite journal|title=Phenyl Vinyl Sulfone and Sulfoxide|author=Leo A. Paquette, Richard V. C. Carr|journal=Org. Synth.|year=1986|volume=64|page=157|doi=10.15227/orgsyn.064.0157}}</ref> For example, dimethyl sulfide oxidizes to dimethyl sulfoxide and then to dimethyl sulfone.<ref name="ISBN 9780534389512"/>

===From preformed SO<sub>2</sub> moieties=== :[[Image:Sulfolane synthesis.png|upright=1.5|right|thumb|Synthesis of sulfolane by hydrogenation of sulfolene.]] Sulfur dioxide participates in cycloaddition reactions with dienes.<ref>{{cite journal|title=Isoprene Cyclic Sulfone|author=Robert L. Frank and Raymond P. Seven|journal=Org. Synth.|year=1949|volume=29|pages=59|doi=10.15227/orgsyn.029.0059}}</ref> For example, the industrially useful solvent sulfolane is prepared by addition of sulfur dioxide to buta-1,3-diene followed by hydrogenation of the resulting sulfolene.<ref name=Ullmann>{{Ullmann | first = Hillis O. | last = Folkins | chapter = Benzene | date = 2005 | doi = 10.1002/14356007.a03_475}}</ref>

Sulfones are prepared under conditions used for Friedel–Crafts reactions using sources of {{chem|RSO|2|+}} derived from sulfonyl halides and sulfonic acid anhydrides. Lewis acid catalysts such as {{chem2|AlCl3}} and {{chem2|FeCl3}} are required.<ref>{{cite journal |author1=Truce, W. E. |author2=Vriesen |author3=C. W. | title = Friedel—Crafts Reactions of Methanesulfonyl Chloride with Benzene and Certain Substituted Benzenes| year = 1953 | journal = J. Am. Chem. Soc. | volume = 75 | pages = 5032–5036 | doi = 10.1021/ja01116a043 | issue = 20|bibcode=1953JAChS..75.5032T }}</ref><ref>{{Cite journal | last1 = Répichet | first1 = S. | last2 = Le Roux | first2 = C. | last3 = Hernandez | first3 = P. | last4 = Dubac | first4 = J. | last5 = Desmurs | first5 = J. R. | title = Bismuth(III) Trifluoromethanesulfonate: An Efficient Catalyst for the Sulfonylation of Arenes | doi = 10.1021/jo9902603 | journal = The Journal of Organic Chemistry | volume = 64 | issue = 17 | pages = 6479–6482 | year = 1999 }}</ref><ref>{{cite journal |author1=Truce, W. E. |author2=Milionis, J. P. | title = Friedel-Crafts Cyclization of ω-Phenylalkanesulfonyl Chlorides | year = 1952 | journal = J. Am. Chem. Soc. | volume = 74 | pages = 974–977 | doi = 10.1021/ja01124a031 | issue = 4}}</ref>

Sulfones have been prepared through sulfinate anion alkylation.<ref>{{cite journal|title=4,4'-Diaminodiphenylsulfone|author1=C. W. Ferry|author2= J. S. Buck|author3= R. Baltzly| journal=Organic Syntheses |year=1942|volume=22|pages=31|doi=10.15227/orgsyn.022.0031}}</ref> S<sub>N</sub>2 displacement of a wide variety of halides gives exclusively sulfones...<chem display=block>ArSO2Na + Ar'Cl -> Ar(Ar')SO2 + NaCl</chem> ...but some highly active alkylating agents give a sulfinate ester instead.<ref name="Mayr">{{cite journal|doi=10.1002/anie.201007100 | pmid=21726020 | volume=50 | issue=29 | title=Farewell to the HSAB Treatment of Ambident Reactivity | journal=Angewandte Chemie International Edition | pages=6497–6499 | last1 = Mayr | first1 = Herbert| year=2011 | bibcode=2011ACIE...50.6470M |postscript=none}}, an excerpt from {{cite thesis|url=https://edoc.ub.uni-muenchen.de/12479/1/Breugst_Martin.pdf#page=323|pages=378&ndash;381|type=PhD dissertation|title=A Marcus-Theory-Based Approach to Ambident Reactivity|first=Robert Martin|last=Breugst|year=2010|publisher=Ludwig-Maximilians-Universität München}}</ref> The ester may or may not rearrange to the sulfone<ref>{{Ullmann|doi=10.1002/14356007.a25_461|title=Sulfinic Acids and Derivatives|first=Rüdiger|last=Schubart|p=682}}</ref> via dissociation-association.<ref name=Mayr/> Absent a nucleophilic catalyst, sulfinate esters generally do not rearrange thermally to the sulfone,<ref>{{cite journal|doi=10.1021/ja01157a018|date=Jan 1950|title=Thermal rearrangement of allyl-type sulfoxides, sulfones and sulfinates|first1=Arthur C.|last1=Cope|first2=Dwight E.|last2=Morrison|first3=Lamar|last3=Field|volume=72|page=60|orig-date=21 June 1949|journal= Journal of the American Chemical Society|issue=1 |bibcode=1950JAChS..72...59C }}</ref> but allyl, propargyl,<ref>{{cite journal | last1=Braverman | first1=Samuel | last2=Pechenick | first2=Tatiana | title=Facile preparation and rearrangement of allylic dialkoxy disulfides | journal=Tetrahedron Letters | volume=43 | issue=3 | date=2002 | doi=10.1016/S0040-4039(01)02174-8 | pages=499–502 | url=https://linkinghub.elsevier.com/retrieve/pii/S0040403901021748 | url-access=subscription }}</ref> and benzyl<ref>{{cite journal|doi=10.1039/JR9300001676|first1=Joseph|last1=Kenyon|first2=Henry|last2=Phillips|title=The optical instability of tercovalent carbonium kations|date=3 June 1930|journal=Journal of the Chemical Society}}</ref> sulfinates can rearrange when heated neat.

===Reactions=== A relatively inert functional group, sulfones are typically less oxidizing and only 4&nbsp;bel more acidic than sulfoxides.<ref name=CS07 /> They eventually eliminate to an alkene in base,<ref>Smith (2020), ''March's Organic Chemistry'', rxn.&nbsp;17-10.</ref> but leave about 9&nbsp;bel more slowly than chloride.<ref name=Chameleons />{{Reference page|page=109}} In the Ramberg–Bäcklund reaction and the Julia olefination, sulfones eliminate sulfur dioxide to form an alkene.<ref name=CS07>{{cite book | first1 = Francis A. | last1 = Carey | first2 = Richard J. | last2 = Sundberg | title = Advanced Organic Chemistry | publisher = Springer | location = Berlin | year = 2007 | isbn = 978-0-387-68354-6}}</ref>

Sulfones are strongly electron-withdrawing,<ref>{{Cite book |last1=Kharasch |first1=Norman |url=https://books.google.com/books?id=v7b9BAAAQBAJ&q=Desulfonylation+reactions&pg=PA115 |title=The Chemistry of Organic Sulfur Compounds |last2=Meyers |first2=Cal Y. |date=2013-10-22 |publisher=Elsevier |isbn=978-1-4831-5611-8 |language=en}}</ref> and vinyl sulfones are electrophilic Michael acceptors.<ref name=eros>{{cite book |doi=10.1002/047084289X.rd476.pub2 |chapter=Divinyl Sulfone |title=Encyclopedia of Reagents for Organic Synthesis |date=2021 |last1=Lucchi |first1=Ottorino |last2=Fabbri |first2=Davide |last3=Santoyo-Gonzalez |first3=Francisco |last4=Hernandez-Mateo |first4=Fernando |last5=Lopez-Jaramillo |first5=F. Javier |last6=Ortega-Muñoz |first6=Mariano |pages=1–8 |isbn=978-0-471-93623-7 }}</ref>

The behavior of the α carbon depends on context. Non-nucleophilic bases deprotonate, giving an enolate-like carbanion.<ref name=Chameleons/>{{rp|107}} Contrariwise, Lewis acids on the sulfone oxygens give a Pummerer-like electrophile that undergoes nucleophilic substitution.<ref name=Chameleons>{{Cite journal |last=Trost |first=Barry Martin |date=1988-01-01 |title=Chemical Chameleons. Organosulfones as Synthetic Building Blocks |url=https://academic.oup.com/bcsj/article/61/1/107/7344738 |journal=Bulletin of the Chemical Society of Japan |language=en |volume=61 |issue=1 |pages=107–124 |doi=10.1246/bcsj.61.107 |issn=0009-2673}}</ref>{{Reference page|pages=117}}

Sulfones can also undergo reductive desulfonylation.<ref name=Chameleons />{{Reference page|page=108}}

==Applications== Sulfolane is used to extract valuable aromatic compounds from petroleum.<ref name=Ullmann/>

===Polymers=== Some polymers containing sulfone groups are useful engineering plastics. They exhibit high strength and resistance to oxidation, corrosion, high temperatures, and creep under stress. For example, some are valuable as replacements for copper in domestic hot water plumbing.<ref>{{cite book | last = Fink | first = Johannes | title = High Performance Polymers | publisher = William Andrew | location = Norwich | year = 2008 | isbn = 978-0-8155-1580-7}}</ref> Precursors to such polymers are the sulfones bisphenol S and 4,4′-dichlorodiphenyl sulfone.<ref>{{Ullmann |first1= David |last1= Parker |first2=Jan |last2=Bussink | first3=Hendrik T. | last3=Grampel | first4=Gary W. | last4=Wheatley | first5=Ernst‐Ulrich | last5=Dorf | first6=Edgar | last6=Ostlinning | first7=Klaus | last7=Reinking | first8=Frank | last8=Schubert | first9=Oliver | last9=Jünger |title= Polymers, High‐Temperature |doi= 10.1002/14356007.a21_449.pub3}}</ref>

===Pharmacology=== [[file:Dapsone.svg|thumb|222px|Dapsone, an antibiotic used for the treatment of leprosy.<ref>{{cite book |author1=Thomas L. Lemke |title=Foye's Principles of Medicinal Chemistry |date=2008 |publisher=Lippincott Williams & Wilkins |isbn=9780781768795 |page=1142 |url=https://books.google.com/books?id=R0W1ErpsQpkC&pg=PA1142 |url-status=live |archive-url=https://web.archive.org/web/20160304193954/https://books.google.ca/books?id=R0W1ErpsQpkC&pg=PA1142 |archive-date=2016-03-04}}</ref>]] Examples of sulfones in pharmacology include dapsone, a drug formerly used as an antibiotic to treat leprosy, dermatitis herpetiformis, tuberculosis, or pneumocystis pneumonia (PCP). Several of its derivatives, such as promin, have similarly been studied or actually been applied in medicine, but in general sulfones are of far less prominence in pharmacology than for example the sulfonamides.<ref>{{cite book | first1 = Charles R. | last1 = Craig | first2 = Robert E. | last2 = Stitzel | title = Modern Pharmacology with Clinical Applications | publisher = Lippincott Williams & Wilkins | location = Hagerstwon | year = 2004 | isbn = 978-0-7817-3762-3}}</ref><ref>{{cite book | first1 = Victor Alexander | last1 = Drill | first2 = Joseph R. | last2 = Di Palma | title = Drill's Pharmacology in Medicine | publisher = McGraw-Hill | location = New York | year = 1971 | isbn = 978-0-07-017006-3}}</ref>

==See also== {{Commons category|Sulfones}} *Organosulfur chemistry *Sulfonanilide *Sulfoxide *Sulfonic acid (–OH substituent)

==References== {{Reflist|30em}}

{{Functional Groups}}

Category:Sulfones Category:Functional groups