Disiamylborane

Disiamylborane
Skeletal formula of disiamylborane
Names
IUPAC name
Bis(1,2-dimethylpropyl)borane
Identifiers
CAS Number
  • 1069-54-1 checkY
3D model (JSmol)
  • Interactive image
  • Interactive image
ChemSpider
  • 167251 checkY
PubChem CID
  • 192733
UNII
  • 2O6VD8483R ☒N
CompTox Dashboard (EPA)
  • DTXSID40910174 Edit this at Wikidata
InChI
  • InChI=1S/C10H23B/c1-7(2)9(5)11-10(6)8(3)4/h7-11H,1-6H3 checkY
    Key: HXJFQNUWPUICNY-UHFFFAOYSA-N checkY
  • InChI=1/C10H23B/c1-7(2)9(5)11-10(6)8(3)4/h7-11H,1-6H3
    Key: HXJFQNUWPUICNY-UHFFFAOYAY
  • CC(C(C)C)BC(C)C(C)C
  • B(C(C(C)C)C)C(C)C(C)C
Properties
Chemical formula
 C10H23B
Molar mass 154.09 g/mol
Melting point 35-40 °C
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references
Chemical compound

Disiamylborane (bis(1,2-dimethylpropyl)borane) is an organoborane with the formula [((CH3)2CHCH(CH3))2BH]2 (abbreviation: Sia2BH). It is a colorless waxy solid that is used in organic synthesis for hydroboration–oxidation reactions. Like most dialkyl boron hydrides, it has a dimeric structure with bridging hydrides.

Reactions

Disiamylborane is prepared by hydroboration of trimethylethylene with diborane.[1] The reaction stops at the secondary borane due to steric hindrance.

Disiamylborane is relatively selective for terminal alkynes and alkenes vs internal alkynes and alkenes. Like most hydroboration, the addition proceeds in an anti-Markovnikov manner.[1] It can be used to convert terminal alkynes, into aldehydes.

The hydroboration process proceeds via an initial dissociation of the dimer.[2]

Related reagents

  • 9-Borabicyclo[3.3.1]nonane (9-BBN).
  • Thexylborane ((1,1,2-trimethylpropyl)borane, ThxBH2), a primary borane obtained by hydroboration of tetramethylethylene.

Naming

The prefix disiamyl is an abbreviation for "di-sec-isoamyl", where sec-isoamyl ("secondary isoamyl") is an archaic name for the 1,2-dimethylpropyl group (amyl being a obsolescent synonym of pentyl).

References

  1. ^ a b Eric J. Leopold (1986). "Selective Hydroboration of a 1,3,7-Triene: Homogeraniol". Organic Syntheses. 64: 164. doi:10.15227/orgsyn.064.0164.
  2. ^ Chandrasekharan, J.; Brown, Herbert C. (1985). "Hydroboration kinetics. 11. A reinvestigation of the kinetics of hydroboration of representative alkenes with disiamylborane dimer. Conclusive evidence for the dissociation mechanism in the hydroboration of alkenes with dialkylborane dimers". The Journal of Organic Chemistry. 50 (4): 518–520. doi:10.1021/jo00204a019.