Norbornene

Norbornene[1]
Names
Preferred IUPAC name
Bicyclo[2.2.1]hept-2-ene
Other names
Norbornylene
Norcamphene
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.007.152 Edit this at Wikidata
EC Number
  • 207-866-0
UNII
  • InChI=1S/C7H10/c1-2-7-4-3-6(1)5-7/h1-2,6-7H,3-5H2 ☒N
    Key: JFNLZVQOOSMTJK-UHFFFAOYSA-N ☒N
  • InChI=1/C7H10/c1-2-7-4-3-6(1)5-7/h1-2,6-7H,3-5H2
    Key: JFNLZVQOOSMTJK-UHFFFAOYAB
  • C1=CC2CCC1C2
Properties
C7H10
Molar mass 94.157 g·mol−1
Appearance White solid
Melting point 42 to 46 °C (108 to 115 °F; 315 to 319 K)
Boiling point 96 °C (205 °F; 369 K)
Hazards
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 3: Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point between 23 and 38 °C (73 and 100 °F). E.g. gasolineInstability 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calciumSpecial hazards (white): no code
2
3
1
Flash point −15 °C (5 °F; 258 K)
Related compounds
Related compounds
 Nadic anhydride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

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 1 and 4. The molecule carries a double bond which induces significant ring strain and significant reactivity.

Production

Norbornene is made by a Diels–Alder reaction of cyclopentadiene and ethylene. Many substituted norbornenes can be prepared similarly.[2][3] 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.[4]

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.[5]

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.[6]

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

References

  1. ^ Norbornene MSDS
  2. ^ Binger, Paul; Wedemann, Petra; Brinker, Udo H. "Cyclopropene: A New Simple Synthesis and its Diels-Alder Reaction with Cyclopentadiene". Organic Syntheses; Collected Volumes, vol. 10, p. 231.
  3. ^ Oda, Masaji; Kawase, Takeshi; Okada, Tomoaki; Enomoto, Tetsuya. "2-Cyclohexene-1,4-dione". Organic Syntheses; Collected Volumes, vol. 9, p. 186.
  4. ^ Thansandote, Praew; Chong, Eugene; Feldmann, Kai-Oliver; Lautens, Mark (21 May 2010). "Palladium-Catalyzed Domino C−C/C−N Coupling Using a Norbornene Template: Synthesis of Substituted Benzomorpholines, Phenoxazines, and Dihydrodibenzoxazepines". The Journal of Organic Chemistry. 75 (10): 3495–3498. doi:10.1021/jo100408p. PMID 20423091.
  5. ^ Hoyle, Charles E.; Bowman, Christopher N. (2010). "Thiol–Ene Click Chemistry". Angewandte Chemie International Edition. 49 (9): 1540–1573. doi:10.1002/anie.200903924.
  6. ^ Delaude, Lionel; Noels, Alfred F. (2005). "Metathesis". Kirk-Othmer Encyclopedia of Chemical Technology. Weinheim: Wiley-VCH. doi:10.1002/0471238961.metanoel.a01. ISBN 978-0471238966.