Catecholborane

Catecholborane
Names


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^Y
3D model (JSmol)	Interactive image Interactive image
ChemSpider	10617125^Y
ECHA InfoCard	100.005.447
InChI InChI=1S/C6H5BO2/c1-2-4-6-5(3-1)8-7-9-6/h1-4,7H^Y Key: CENMEJUYOOMFFZ-UHFFFAOYSA-N^Y InChI=1/C6H5BO2/c1-2-4-6-5(3-1)8-7-9-6/h1-4,7H Key: CENMEJUYOOMFFZ-UHFFFAOYAI
SMILES [B]1OC2=CC=CC=C2O1 c1cccc2OBOc12
Properties
Chemical formula	C₆H₅BO₂
Molar mass	119.92 g/mol
Appearance	Colorless liquid
Density	1.125 g/cm³, liquid
Melting point	12 °C (54 °F; 285 K)
Boiling point	50 °C (122 °F; 323 K) at 50 mmHg
Hazards
R-phrases (outdated)	R11, R14, R34
S-phrases (outdated)	S16, S26, S36/37/39, S43, S45
NFPA 704	4 1 2 W
Flash point	2 °C (36 °F; 275 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y (what is ^YN ?)
Infobox references

Catecholborane (abbreviated HBcat) is an organoboron compound that is useful in organic synthesis. This colourless liquid is a derivative of catechol and a borane, having the formula C₆H₄O₂BH.

Traditionally catecholborane is produced by treating catechol with borane (BH₃) in a cooled solution of THF. However, this method results in a loss of 2 mole equivalents of the hydride. Nöth and Männig devised a more economical method involves the reaction of alkali-metal boron hydride (LiBH₄, NaBH₄, of KBH₄) with tris(catecholato)bisborane in an ethereal solvent such as diethyl ether. In 2001 Herbert Brown released an additional procedure for catecholborane synthesis. His method involves treating 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.

Unlike borane itself or alkylboranes, catechol borane exists as a monomer. This behavior is a consequence of the electronic influence of the alkoxy groups that diminish the Lewis acidity of the boron centre. Pinacolborane adopts a similar structure.

Catechol borane is less reactive than borane itself.

When catecholborane is treated with an alkyne, usually a terminal alkyne, through hydroboration a trans vinylborane is formed. The product is a precursor to the Suzuki reaction.

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