Basketane

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Basketane
Names
Preferred IUPAC name
Pentacyclo[4.4.0.02,5.03,8.04,7]decane
Identifiers
3D model (
JSmol
)
ChemSpider
  • InChI=1S/C10H12/c1-2-4-7-5-3(1)6-8(4)10(7)9(5)6/h3-10H,1-2H2
    Key: QKWLQWFMFQOKET-UHFFFAOYSA-N
  • InChI=1/C10H12/c1-2-4-7-5-3(1)6-8(4)10(7)9(5)6/h3-10H,1-2H2
    Key: QKWLQWFMFQOKET-UHFFFAOYAB
  • C2CC5C1C4C3C1C2C3C45
Properties
C10H12
Molar mass 132.206 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Basketane is a polycyclic alkane with the chemical formula C10H12. The name is taken from its structural similarity to a basket shape. Basketane was first synthesized in 1966, independently[1] by Masamune[2] and Dauben and Whalen.[3] A patent application published in 1988 used basketane, which is a hydrocarbon, as a source material in doping thin diamond layers because of the molecule's high vapor pressure, carbon ring structure, and fewer hydrogen-to-carbon bond ratio.[4]

Chemical nomenclature

In the year 1989 and before the synthesis of basketane, historic chemists were intrigued by the structural make-up of molecules, specifically those in objects seen in everyday life.[5] Using supramolecular chemistry, molecules such as cubane and basketane were named according to their corresponding shape and historically revealed certain characteristics and personal motives of chemists at that time.[5] Naming these uniquely shaped molecules were also done considering chemical nomenclature such as adding "-anes" for single carbon-carbon bonds and "-enes" for double carbon-carbon bonds to the end of the appropriate molecules.[6]

Synthesis

One synthesis of basketane begins with a Diels–Alder reaction between cyclooctatetraene (1) and maleic anhydride (2), giving the polycyclic anhydride 3, which photoisomerizes in acetone via an intramolecular cyclization to give 4 at a 40% yield. Hydrolysis of the anhydride followed by treatment with lead tetraacetate affords the unsaturated basketene (5), which is then hydrogenated to basketane (6).[2]

An alternative synthetic route with better overall yield uses 1,4-benzoquinone and cyclohexa-1,3-diene as starting materials. 1,4-Benzoquinone (1) is first converted to 2,5-dibromo-1,4-benzoquinone (2), which reacts in a Diels–Alder reaction with cyclohexa-1,3-diene (3) to form the polycyclic diketone 4. This diketone photoisomerizes to 1,6-dibromopentacyclo[6.4.0.03,6.04,12.05,9]dodeca-2,7-dione (5), which undergoes a pseudo-Favorskii rearrangement in a 25% aqueous solution of sodium hydroxide, giving the dicarboxylic acid 6. The acid is decarboxylated with a modified Hunsdiecker reaction to a dibromide 7, which is reductively debrominated with tributyltin hydride to basketane (8) at a 11% yield relative to the starting material cyclohexa-1,3-diene.[7]

A 1994 synthesis starts with homocubanone, a cubane derivative, forming basketane via the basketyl

free energy barriers around 0.3 kcal/mol.[10]

Properties and reactions

The C-C-C and H-C-C bond angles in basketane and several other cages deviate from 109.5 degrees, i.e., they are

strained rings.[11] The strain energy is reflected in high heat of combustion.[11]

Metal-catalyzed rearrangements

Transition metals catalyze the

valence isomerization of basketane and substituted derivatives. Silver perchlorate catalyzes its isomerization to the compound snoutane
.

Other transition metals catalyze the formation of a snoutane derivative with a tricyclic diene. The ratio of the products depends on the nature of the catalyst used and the substitutions on the basketane.[12]

Basketane absorbs an equivalent amount of hydrogen gas in the presence of palladium on carbon, After some initial confusion, it was shown that the C3-C4 bond is hydrogenolyzed to give the dihydrobasketane tetracyclo[4.4.0.02,5.03,8]decane.[13] Further hydrogenation cleaves the C5-C6 bond to give the hydrocarbon twistane.[14]

See also

References

  1. doi:10.1021/cr00095a004
    .
  2. ^
    doi:10.1016/S0040-4039(00)70232-2
    .
  3. doi:10.1016/S0040-4039(01)99958-7
    .
  4. Hughes Aircraft Co.
     , since withdrawn.
  5. ^
    S2CID 94479873
    .
  6. ^ "2.3.2". www.nanomedicine.com. Retrieved 2021-02-23.
  7. ISSN 0022-3263
    .
  8. ISSN 0002-7863
    .
  9. PMID 18179235
    .
  10. PMID 18179235
    .
  11. ^
    ISSN 0009-2665
    .
  12. ISSN 0002-7863
    .
  13. ISSN 0009-2940
    .
  14. ISSN 0009-2940
    .

Further reading
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