BINAP
From Wikipedia, the free encyclopedia
| BINAP | |
|---|---|
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| IUPAC name | 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl |
| Other names | BINAP |
| Identifiers | |
| CAS number | [76189-55-4 (R), 76189-56-5 (S)] |
| Properties | |
| Molecular formula | C44H32P2 |
| Molar mass | 622.67 g/mol |
| Appearance | colorless solid |
| Melting point |
239-241 °C (R), 238-240 °C (S) |
| Solubility in water | organic solvents |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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BINAP is an acronym for the organophosphorus compound 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl. This chiral ligand is widely used in asymmetric synthesis. It consists of a pair of 1-diphenylphosphinonaphthyl groups linked at the 2 positions (Figure 1). This C2-symmetric framework lacks stereogenic atom (see axial chirality ). The barrier to racemization is high due to steric hindrance that limits rotation about the bond linking the naphthyl rings. The dihedral angle is approximately 90˚.
BINAP is used in organic synthesis for enantioselective transformations catalyzed by its complexes of ruthenium, rhodium, and palladium. As pioneered by Ryoji Noyori and his co-workers, Rh complexes of BINAP are useful for the synthesis of (-)-menthol. This synthetic method was industrialized by Takasago International Corporation. In part for this work, Noyori was awarded the 2001 Nobel Prize in Chemistry.
BINAP is prepared from BINOL (1,1'-bi-2-naphthol) via its bis-triflate derivatives. Both the R and S enantiomers as well as the racemate are commercially available.
[edit] References
- ^ "Binap: An industrial approach to manufacture".
- BINAP synthesis in Organic Syntheses, Coll. Vol. 10, p.112 (2004); Vol. 76, p.6 (1999) Article.
- Asymmetric hydrogenation of methyl 3-oxobutanoate to (R)-Methyl 3-hydroxybutanoate with a ruthenium BINAP catalyst in Organic Syntheses, Coll. Vol. 9, p.589 (1998); Vol. 71, p.1 (1993) Article.
