Catecholborane

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Catecholborane

IUPAC name	Catecholborane
Other names	1,3,2-benzodioxaborole 7,9-dioxa-8λ2-borabicyclo[4.3.0]nona-1,3,5-triene
Identifiers
CAS number	[274-07-7]
SMILES	[B]1OC2=CC=CC=C2O1
Properties
Molecular formula	C₆H₅BO₂
Molar mass	119.92 g/mol
Appearance	Colorless liquid
Density	1.125 g/cm³, liquid
Melting point	12 °C
Boiling point	50 °C
Hazards
NFPA 704	4 1 2 W
R-phrases	R11, R14, R34
S-phrases	S16, S26, S36/37/39, S42, S45
Flash point	2 °C
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Catecholborane, or BHcat, is a derivative of catechol and a boron hydride, with the formula C₆H₄O₂BH. It is commonly used in organic syntheses.

1 Synthesis
2 Reactions
- 2.1 Preparation of an organoborane
- 2.2 Reduction of β-hydroxy ketones
3 See also
4 References

[edit] Synthesis

Traditionally catecholborane commonly is produced by reacting catechol with borane (BH₃) in a cooled solution of THF. However, this method results in a loss of 2 mole equivalents of the hydride.

Heinrich Noth and Detlef Mannig devised a method that allows a more efficient recovery of the final product, catecholborane, and subsequently a greater yield. Their method involves reacting an alkali-metal boron hydride (LiBH₄, NaBH₄, of KBH₄) with tris(catecholato)bisborane in an ether solvent such as diethyl ether or diethylene glycol.^[1]

In 2001 Herbert Brown released an additional procedure for catecholborane synthesis. His method involves reacting tri-O-phenylene bis-borate with diborane in a solution of either triglyme or tetraglyme. Brown claimed his method produces 85% yield of 97% pure product, catecholborane.^[2]

[edit] Reactions

[edit] Preparation of an organoborane

When catecholborane is reacted with an alkyne, usually a terminal alkyne, through hydroboration a trans vinylborane is formed. This is the precursor to the Suzuki reaction.^[3]