Catecholborane

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

Additional recommended knowledge

Recognize and detect the effects of electrostatic charges on your balance

How to quickly check pipettes?

Don't let static charges disrupt your weighing accuracy

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]

Reactions

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]

Reduction of β-hydroxy ketones

Catecholborane may be used as a stereoselective reducing agent when converting β-hydroxy ketones to syn 1,3-diols.^[4]

See also

• Catechol

References

1. ^ http://www.freepatentsonline.com/4739096.html
2. ^ http://pubs.acs.org/cgi-bin/abstract.cgi/oprdfk/2000/4/i06/abs/op000291w.html
3. ^ Janice Gorzynski Smith. Organic Chemistry: Second Ed. 2008. pp 1007
4. ^ http://evans.harvard.edu/pdf/evans135.pdf