Cis-Cyclooctene
{{DISPLAYTITLE:cis-Cyclooctene}}
{{chembox
| Reference ={{cite web |url= http://www.sigmaaldrich.com/catalog/search/ProductDetail/ALDRICH/125482 |title= cis-Cyclooctene |publisher= Sigma-Aldrich }}
| Name =cis-Cyclooctene
| ImageFile =Cyclooctene.svg
| ImageSize = 106 px
| PIN = (Z)-Cyclooctene
| OtherNames = cis-Cyclooctene
|Section1={{Chembox Identifiers
| ChemSpiderID = 553642
| InChI = 1/C8H14/c1-2-4-6-8-7-5-3-1/h1-2H,3-8H2/b2-1-
| InChIKey = URYYVOIYTNXXBN-UPHRSURJBT
| CASNo =931-87-3
| PubChem =638079
| ChEBI = 229204
| EINECS = 213-243-4
| UNII = AE340T3540
| StdInChI=1S/C8H14/c1-2-4-6-8-7-5-3-1/h1-2H,3-8H2/b2-1-
| StdInChIKey = URYYVOIYTNXXBN-UPHRSURJSA-N
| SMILES = C\1=C\CCCCCC/1
}}
|Section2={{Chembox Properties
| C=8 | H=14
| Appearance =
| Density =0.846 g/mL
| MeltingPtC = -16
| BoilingPtC = 145 to 146
| BoilingPt_notes =
| Solubility =
}}
|Section3={{Chembox Hazards
| MainHazards =
| FlashPt =
| AutoignitionPt =
| GHSPictograms = {{GHS02}}{{GHS08}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|226|304}}
| PPhrases = {{P-phrases|210|233|240|241|242|243|280|301+310|303+361+353|331|370+378|403+235|405|501}}
}}
}}
cis-Cyclooctene is a cycloalkene with the formula (CH2)6(CH)2. It is a colorless liquid that is used industrially to produce a polymer. It is also a ligand in organometallic chemistry.
Cyclooctene is the smallest cycloalkene that can be isolated as both the cis- and trans-isomer.{{cite journal |first1= Ulrich |last1= Neuenschwander |first2= Ive |last2= Hermans |doi= 10.1021/jo202176j |title= The Conformations of Cyclooctene: Consequences for Epoxidation Chemistry |journal= J. Org. Chem. |volume= 76 |issue= 24 |pages= 10236–10240 |year= 2011 |pmid= 22077196 }} cis-Cyclooctene is shaped like the 8-carbon equivalent chair conformation of cyclohexane.
| style="margin-left:auto;margin-right:auto;"
| 150px | align="right"|150px |
| align="center"
| cis-Cyclooctene | (Rp)-trans-Cyclooctene in crown conformation |
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Uses and reactions
Cyclooctene undergoes ring-opening metathesis polymerization to give polyoctenamers, which are marketed under the name Vestenamer.{{cite encyclopedia |title=Metathesis |encyclopedia=Kirk-Othmer Encyclopedia of Chemical Technology |author1=Lionel Delaude |author2=Alfred F. Noels |year=2005| doi=10.1002/0471238961.metanoel.a01 |place=Weinheim |publisher=Wiley-VCH |isbn=0471238961}}
cis-Cyclooctene (COE) is a substrate known for quite selectively forming the epoxide, as compared to other cycloalkenes, e.g. cyclohexene. Low amounts of radical by-products are found only. This behaviour is attributed to the difficulty of functionalizing allylic CH centers, which almost orthogonal allylic C-H bonds. Therefore, if radicals are around, they tend to form epoxide via an addition-elimination mechanism.
It is used as an easily displaced ligand in organometallic chemistry, e.g. chlorobis(cyclooctene)rhodium dimer and chlorobis(cyclooctene)iridium dimer.