Benzvalene

Benzvalene
IUPAC name

tricyclo[3.1.0.02,6]hex-3-ene
Identifiers
PubChem 136470
Jmol-3D images Image 1
Properties
Molecular formula C6H6
Molar mass 78.1 g/mol
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Benzvalene is an organic compound and one of several isomers of benzene.[1]. It was synthesised in 1971 by Thomas J. Katz et al.[2][3]

The 1971 synthesis consisted of treating cyclopentadiene with methyllithium in dimethylether and then with dichloromethane and methyllithium in at -45°C. The hydrocarbon in solution was described as having an extraordinary foul odor. Due to the high steric strain present in benzvalene, the pure compound easily detonates, for example by scratching.

The compound converts to benzene with a chemical half-life of approximately 10 days. This symmetry forbidden transition is believed to take place through a diradical intermediate [4]

Polybenzvalene

Benzvalene can be polymerized in a ROMP process to polybenzvalene [5]. This polymer contains highly strained bicyclobutane rings which again makes it a sensitive material. The rings can be isomerized to 1,3-dienes and for this reason polybenzvalene has been investigated as a precursor to polyacetylene.

References

  1. ^ Christl, M. (1981). "Benzvalene—Properties and Synthetic Potential". Angewandte Chemie International Edition in English 20 (67): 529–521. doi:10.1002/anie.198105291.  edit
  2. ^ Katz, T. J.; Wang, E. J.; Acton, N. (1971). "Benzvalene synthesis". Journal of the American Chemical Society 93 (15): 3782. doi:10.1021/ja00744a045.  edit
  3. ^ Katz, T. J.; Roth, R. J.; Acton, N.; Carnahan, E. J. (1999). "Synthesis of Benzvalene†". The Journal of Organic Chemistry 64 (20): 7663. doi:10.1021/jo990883g.  edit
  4. ^ Rearrangements and interconversions of compounds of the formula (CH)n Lawrence T. Scott, Maitland. Jones Chem. Rev., 1972, 72 (2), pp 181–202 doi:10.1021/cr60276a004
  5. ^ Swager, T. M.; Dougherty, D. A.; Grubbs, R. H. (1988). "Strained rings as a source of unsaturation: polybenzvalene, a new soluble polyacetylene precursor". Journal of the American Chemical Society 110 (9): 2973. doi:10.1021/ja00217a049.  edit