benzvalene

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| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 424755299

| ImageFile = Benzvalene.svg

| ImageSize = 150px

| PIN = Tricyclo[3.1.0.0^2,6]hex-3-ene

| OtherNames =

|Section1={{Chembox Identifiers

| CASNo_Ref = {{cascite|changed|CAS}}

| CASNo = 659-85-8

| PubChem = 136470

| SMILES = C1=CC2C3C1C23

| InChI = 1/C6H6/c1-2-4-5-3(1)6(4)5/h1-6H

| ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}}

| ChemSpiderID = 120239

| InChIKey = VMQPMGHYRISRHO-UHFFFAOYAJ

| StdInChI_Ref = {{stdinchicite|changed|chemspider}}

| StdInChI = 1S/C6H6/c1-2-4-5-3(1)6(4)5/h1-6H

| StdInChIKey_Ref = {{stdinchicite|changed|chemspider}}

| StdInChIKey = VMQPMGHYRISRHO-UHFFFAOYSA-N

}}

|Section2={{Chembox Properties

| C=6 | H=6

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|Section3={{Chembox Hazards

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}}

Benzvalene is an organic compound and one of several isomers of benzene.{{Cite journal| doi = 10.1002/anie.198105291| title = Benzvalene—Properties and Synthetic Potential| year = 1981| last1 = Christl | first1 = M.| journal = Angewandte Chemie International Edition in English| volume = 20| issue = 67| pages = 529–546}} It was first synthesized in 1967 by K. E. Wilzbach et al. {{Cite journal| doi = 10.1021/ja00980a053| title = Benzvalene, the Tricyclic Valence Isomer of Benzene| year = 1967| last1 = Wilzbach | first1 = K. E. | last2 = Ritscher | first2 = J. S. | last3 = Kaplan | first3 = L. | journal = Journal of the American Chemical Society| volume = 89| issue = 4| pages = 1031 }} via photolysis of benzene and the synthesis was later improved by Thomas J. Katz et al.{{Cite journal| doi = 10.1021/ja00744a045| title = Benzvalene synthesis| year = 1971| last1 = Katz | first1 = T. J.| last2 = Wang | first2 = E. J.| last3 = Acton | first3 = N.| journal = Journal of the American Chemical Society| volume = 93| issue = 15| pages = 3782}}{{Cite journal| doi = 10.1021/jo990883g| title = Synthesis of Benzvalene | year = 1999| last1 = Katz | first1 = T. J.| last2 = Roth | first2 = R. J.| last3 = Acton | first3 = N.| last4 = Carnahan | first4 = E. J.| journal = The Journal of Organic Chemistry| volume = 64| issue = 20| pages = 7663}}

The 1971 synthesis consisted of treating cyclopentadiene with methyllithium in dimethyl ether and then with dichloromethane and methyllithium in diethyl ether at −45 °C. It can also be formed in low yield (along with fulvene and Dewar benzene) by irradiation of benzene at 237 to 254 nm.{{Cite journal|last1=Kaplan|first1=Louis|last2=Wilzbach|first2=K. E.|date=1968-06-01|title=Photolysis of benzene vapor. Benzvalene formation at wavelengths 2537-2370 A|journal=Journal of the American Chemical Society|volume=90|issue=12|pages=3291–3292|doi=10.1021/ja01014a086|issn=0002-7863}} The hydrocarbon in solution was described as having an extremely foul odor. Due to the high steric strain present in benzvalene, the pure compound (~71 kcal/mol higher in energy than benzene) 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.{{Cite journal | doi = 10.1021/cr60276a004| title = Rearrangements and interconversions of compounds of the formula (CH)n| journal = Chemical Reviews| volume = 72| issue = 2| pages = 181| year = 1972| last1 = Scott| first1 = Lawrence T.| last2 = Jones| first2 = Maitland}}