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 ;
3D model (JSmol)	Interactive image;
Abbreviations	B2pin2
ChemSpider	2015334 ;
ECHA InfoCard	100.111.245
PubChem CID	2733548;
CompTox Dashboard (EPA)	DTXSID30369935 ;
	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). verify (what is ?) Infobox references

Bis(pinacolato)diboron is covalent compound containing two boron atoms and two pinacolato ligands. It has the formula [(CH₃)₄C₂O₂B]₂; the pinacol groups are sometimes abbreviated as "pin", so the structure is sometimes represented as B₂pin₂. 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. Unlike some other diboron compounds, B₂pin₂ is not moisture-sensitive and can be handled in air.^[1]

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 alkanes and alkenes. Using various organorhodium or organoiridium catalysts, it can also be installed onto saturated hydrocarbons:^[3]

CH₃(CH₂)₆CH₃ + [pinB]₂ → pinBH + CH₃(CH₂)₇Bpin

These reactions proceed via boryl complexes.

References

^ ^a ^b Tatsuo Ishiyama; Miki Murata; Taka-aki Ahiko; Norio Miyaura (2004). "Bis(pinacolato)diboron". Organic Syntheses; Collected Volumes, vol. 10, p. 115.
^ 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
^ Xinyu Liu "Bis(pinacolato)diboron" Synlett 2003, pp 2442–2443. doi:10.1055/s-2003-43344

[OS-1] Tatsuo Ishiyama; Miki Murata; Taka-aki Ahiko; Norio Miyaura (2004). "Bis(pinacolato)diboron". Organic Syntheses; Collected Volumes, 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

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