{{Chembox |Verifiedfields = changed |Watchedfields = changed |verifiedrevid = 450599059 |Reference = <ref>{{Cite web |url=https://fscimage.fishersci.com/msds/66955.htm |title=Norbornene MSDS |access-date=2005-09-16 |archive-date=2016-03-03 |archive-url=https://web.archive.org/web/20160303172528/https://fscimage.fishersci.com/msds/66955.htm |url-status=dead }}</ref> |ImageFileL1 = Norbornene.png |ImageFileR1 = Norbornene2.png |ImageFile2 = Norbornene3.png |ImageSize2 = 150px |PIN = Bicyclo[2.2.1]hept-2-ene <!-- Nomenclature of Organic Chemistry – IUPAC Recommendations and Preferred Names 2013 (Blue Book) --> |OtherNames = Norbornylene<br>Norcamphene |Section1={{Chembox Identifiers |PubChem = 10352 |ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}} |ChemSpiderID = 9925 |InChI = 1/C7H10/c1-2-7-4-3-6(1)5-7/h1-2,6-7H,3-5H2 |InChIKey = JFNLZVQOOSMTJK-UHFFFAOYAB |StdInChI_Ref = {{stdinchicite|changed|chemspider}} |StdInChI = 1S/C7H10/c1-2-7-4-3-6(1)5-7/h1-2,6-7H,3-5H2 |StdInChIKey_Ref = {{stdinchicite|changed|chemspider}} |StdInChIKey = JFNLZVQOOSMTJK-UHFFFAOYSA-N |CASNo_Ref = {{cascite|correct|CAS}} |CASNo = 498-66-8 |UNII_Ref = {{fdacite|correct|FDA}} |UNII = 2Q51FLS550 |EINECS = 207-866-0 |SMILES = C1=CC2CCC1C2 |ChEBI_Ref = {{ebicite|correct|EBI}} |ChEBI = 52286 |KEGG_Ref = {{keggcite|correct|kegg}} }} |Section2={{Chembox Properties | C=7 | H=10 |Appearance = White solid |MeltingPtC = 42 to 46 |BoilingPtC = 96 }} |Section7={{Chembox Hazards |NFPA-H = 2 |NFPA-F = 3 |NFPA-R = 1 |NFPA-S = |FlashPtC = −15 }} |Section8={{Chembox Related |OtherCompounds = Nadic anhydride }} }}
'''Norbornene''' or '''norbornylene''' or '''norcamphene''' is a highly strained bridged cyclic hydrocarbon. It is a white solid with a pungent sour odor. The molecule consists of a cyclohexene ring with a methylene bridge between carbons 3 and 6. The molecule carries a double bond which induces significant ring strain and significant reactivity.
The name comes from norbornane, from bornane.
==Production== Norbornene can be prepared via Diels–Alder reaction of cyclopentadiene (made ''in situ'' from decomposition of dicyclopentadiene) and ethylene.<ref>{{OrgSynth|prep=cv4p0738|title=Norbornylene|author=J. Meinwald and N. J. Hudak|year=1957|volume=37|page=65}}</ref> Many substituted norbornenes can be prepared similarly.<ref>{{OrgSynth | first1= Paul |last1=Binger |first2=Petra |last2=Wedemann |first3=Udo H. |last3=Brinker| title = Cyclopropene: A New Simple Synthesis and its Diels-Alder Reaction with Cyclopentadiene | collvol = 10 | collvolpages = 231 | prep=v77p0254}}</ref><ref>{{OrgSynth | first1=Masaji |last1=Oda |first2=Takeshi |last2=Kawase |first3=Tomoaki |last3=Okada |first4=Tetsuya |last4=Enomoto | title = 2-Cyclohexene-1,4-dione | collvol = 9 | collvolpages = 186 | prep = cv9p0186}}</ref> Related bicyclic compounds are norbornadiene, which has the same carbon skeleton but with two double bonds, and norbornane which is prepared by hydrogenation of norbornene.
== Reactions == Norbornene undergoes an acid-catalyzed hydration reaction to form norborneol. This reaction was of great interest in the elucidation of the non-classical carbocation controversy.
Norbornene is used in the Catellani reaction and in norbornene-mediated ''meta''-C−H activation.<ref>{{cite journal|last=Thansandote|first=Praew|date=21 May 2010|title=Palladium-Catalyzed Domino C−C/C−N Coupling Using a Norbornene Template: Synthesis of Substituted Benzomorpholines, Phenoxazines, and Dihydrodibenzoxazepines|journal=The Journal of Organic Chemistry|volume=75|issue=10|pages=3495–3498|doi=10.1021/jo100408p|pmid=20423091|last2=Chong|first2=Eugene|last3=Feldmann|first3=Kai-Oliver|last4=Lautens|first4=Mark}}</ref>
Certain substituted norbornenes undergo unusual substitution reactions owing to the generation of the 2-norbornyl cation.
Being a strained ene, norbornenes react readily with thiols in the thiol-ene reaction to form thioethers. This makes norbornene-functionalized monomers ideal for polymerization with thiol-based monomers to form thiol-ene networks.<ref>{{cite journal |last1=Hoyle |first1=Charles E. |last2=Bowman |first2=Christopher N. |title=Thiol–Ene Click Chemistry |journal=Angewandte Chemie International Edition |year=2010 |volume=49 |issue=9 |doi=10.1002/anie.200903924 |pages=1540–1573}}</ref>
===Polynorbornenes=== Norbornenes are important monomers in ring-opening metathesis polymerizations (ROMP). Typically these conversions are effected with ill-defined catalysts. '''Polynorbornenes''' exhibit high glass transition temperatures and high optical clarity.<ref name=KO>{{cite encyclopedia|encyclopedia=Kirk-Othmer Encyclopedia of Chemical Technology|first1=Lionel |last1=Delaude |first2=Alfred F. |last2=Noels|year=2005| doi=10.1002/0471238961.metanoel.a01|place=Weinheim|publisher=Wiley-VCH|isbn = 978-0471238966|chapter = Metathesis}}</ref> :thumb|center|444px|ROMP reaction giving polynorbornene. Like most commercial alkene metathesis processes, this reaction does not employ a well-defined molecular catalyst.
In addition to ROMP, norbornene monomers also undergo vinyl-addition polymerization, and is a popular monomer for use in cyclic olefin copolymers.
Polynorbornene is used mainly in the rubber industry for antivibration (rail, building, industry), antiimpact (personal protective equipment, shoe parts, bumpers) and grip improvement (toy tires, racing tires, transmission systems, transports systems for copiers, feeders, etc.)
Ethylidene norbornene is a related monomer derived from cyclopentadiene and butadiene.
==See also== *Nadic anhydride
==References== {{Reflist|30em}}
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Category:Monomers Category:Norbornanes