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| Catecholborane | |
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| 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 |
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| 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
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| 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 references |
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Catecholborane, or BHcat, is a derivative of catechol and a boron hydride, with the formula C6H4O2BH. It is commonly used in organic syntheses.
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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
References
- ^ Process for producing catecholborane - Patent 4739096
- ^ New Economical, Convenient Procedures for the Synthesis of Catecholborane
- ^ Janice Gorzynski Smith. Organic Chemistry: Second Ed. 2008. pp 1007
- ^ http://evans.harvard.edu/pdf/evans135.pdf
