Bis(pinacolato)diboron

Bis(pinacolato)diboron

Names
IUPAC name 4,4,4',4',5,5,5',5'-octamethyl-2,2'-Bi-(1,3,2-dioxaborolane)
Identifiers
CAS Number	73183-34-3
ChemSpider	2015334
Jmol interactive 3D	Image
PubChem	2733548
InChI InChI=1S/C12H24B2O4/c1-9(2)10(3,4)16-13(15-9)14-17-11(5,6)12(7,8)18-14/h1-8H3 Key: IPWKHHSGDUIRAH-UHFFFAOYSA-N InChI=1/C12H24B2O4/c1-9(2)10(3,4)16-13(15-9)14-17-11(5,6)12(7,8)18-14/h1-8H3 Key: IPWKHHSGDUIRAH-UHFFFAOYAV
SMILES B1(OC(C(O1)(C)C)(C)C)B2OC(C(O2)(C)C)(C)C
Properties
Chemical formula	C12H24B2O4
Molar mass	253.94 g·mol^−1
Melting point	137 to 140 °C (279 to 284 °F; 410 to 413 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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Infobox references

Bis(pinacolato)diboron is a boron containing two pinacolato ligands. With the formula [(CH₃)₄C₂O₂B]₂, it is a colourless solid that is soluble in organic solvents. It is a commercially available reagent for making pinacol boronic esters for organic synthesis.

Preparation and structure

This compound may be prepared by reacting tetrakis(dimethylamino)diboron with pinacol in acidic conditions.^[1] The B-B bond distance is 1.711(6) Å.^[2]

Reactions

The B-B bond adds across alkenes and alkynes to give the 1,2-diborylated alkane and alkenes. In the presence of organorhodium complexes, it can be installed onto saturated hydrocarbons:^[3]

CH₃(CH₂)₆CH₃ + [(CH₃)₄C₂O₂B]₂ → (CH₃)₄C₂O₂BH + (CH₃)CH₂(CH₂)₅CH₃₆C₂O₂

References

1. Tatsuo Ishiyama, Miki Murata, Taka-aki Ahiko, and Norio Miyaura (2004). "Bis(pinacolato)diboron". Org. Synth.; Coll. Vol. 10, p. 115
2. C.Kleeberg, A.G.Crawford, A.S.Batsanov, P.Hodgkinson, D.C.Apperley, Man Sing Cheung, Zhenyang Lin, T.B.Marder "Spectroscopic and Structural Characterization of the CyNHC Adduct of B₂pin₂ in Solution and in the Solid State" J. Org. Chem 2012, vol. 77, pp. 785. doi:10.1021/jo202127c
3. Xinyu Liu "Bis(pinacolato)diboron" Synlett 2003, pp 2442–2443. doi:10.1055/s-2003-43344