Bis(pinacolato)diboron is a
covalent compound
A covalent bond is a chemical bond that involves the sharing of electrons to form electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs. The stable balance of attractive and repulsive forces between atoms ...
containing two
boron
Boron is a chemical element with the symbol B and atomic number 5. In its crystalline form it is a brittle, dark, lustrous metalloid; in its amorphous form it is a brown powder. As the lightest element of the ''boron group'' it has th ...
atoms and two
pinacol
Pinacol is a white solid organic compound. It is a diol that has hydroxyl groups (-OH) on vicinal carbon atoms.
Preparation
It may be produced by the pinacol coupling reaction from
acetone:
Reactions
As a vicinal-diol, it can rearrange t ...
ato ligands. It has the formula
CH3)4C2O2Bsub>2; the pinacol groups are sometimes abbreviated as "pin", so the structure is sometimes represented as B
2pin
2. It is a colourless solid that is soluble in organic solvents. It is a commercially available reagent for making
pinacol boronic ester
A boronic acid is an organic compound related to boric acid () in which one of the three hydroxyl groups () is replaced by an alkyl or aryl group (represented by R in the general formula ). As a compound containing a carbon–boron bond, membe ...
s for
organic synthesis
Organic synthesis is a special branch of chemical synthesis and is concerned with the intentional construction of organic compounds. Organic molecules are often more complex than inorganic compounds, and their synthesis has developed into one o ...
. Unlike some other diboron compounds, B
2pin
2 is not moisture-sensitive and can be handled in air.
[
]
Preparation and structure
This compound may be prepared by treating tetrakis(dimethylamino)diboron with pinacol
Pinacol is a white solid organic compound. It is a diol that has hydroxyl groups (-OH) on vicinal carbon atoms.
Preparation
It may be produced by the pinacol coupling reaction from
acetone:
Reactions
As a vicinal-diol, it can rearrange t ...
in acidic conditions.
Reactions
left, 110px
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:
:CH3(CH2)6CH3 + inBsub>2 → pinBH + CH3(CH2)7Bpin
These reactions proceed via boryl complexes.
Bis(pinacolato)diboron can also be used as reducing agent for example in transition metal catalyzed hydrogenations of alkenes and alkynes.
References
{{reflist
Organoboron compounds
Reagents for organic chemistry
