Barrelene
From Wikipedia, the free encyclopedia
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| Names | |||
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| Preferred IUPAC name
Bicyclo[2.2.2]octa-2,5,7-triene[1] | |||
| Identifiers | |||
3D model (JSmol) |
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PubChem CID |
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CompTox Dashboard (EPA) |
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| Properties | |||
| C8H8 | |||
| Molar mass | 104.15 | ||
| Density | 1.013 g/mL | ||
| Boiling point | 153.7 °C (308.7 °F; 426.8 K) | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Barrelene is a bicyclic organic compound with chemical formula C8H8 and systematic name bicyclo[2.2.2]octa-2,5,7-triene. First synthesized and described by Howard Zimmerman in 1960, the name derives from the resemblance to a barrel, with the staves being three ethylene units attached to two methine groups. It is the formal Diels–Alder adduct of benzene and acetylene. Due to its unusual molecular geometry, the compound is of considerable interest to theoretical chemists.
Iptycenes, with the alkene groups part of an arenes, are related compounds. It is also a starting material for many other organic compounds, such as semibullvalene.
The original Zimmerman synthesis modified in 1969[2] starts from coumalic acid:[note 1]
The synthesis of barrelene as reported by Zimmermann in 1969.
Many alternative routes have been devised since then, one of them starting from benzene oxide:[3][4]
An alternate route that allows synthesis of the parent barrelene system and a variety of substituted barrelenes has also been reported.[5]
