- Chiraphos
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Chiraphos Other names- (2S,3S)-(–)-Bis(diphenylphosphino)butane
- (2R,3R)-(+)-Bis(diphenylphosphino)butane (for the corresponding enantiomer)
Identifiers CAS number 74839-84-2 (R,R-Enantiomer) , 64896-28-2 (S, S-Enantiomer)
PubChem 10113249 ChemSpider 8288775 Jmol-3D images Image 1 - P(c1ccccc1)(c2ccccc2)[C@H]([C@@H](P(c3ccccc3)c4ccccc4)C)C
- InChI=1S/C28H28P2/c1-23(29(25-15-7-3-8-16-25)26-17-9-4-10-18-26)24(2)30(27-19-11-5-12-20-27)28-21-13-6-14-22-28/h3-24H,1-2H3/t23-,24-/m0/s1
Key: FWXAUDSWDBGCMN-ZEQRLZLVSA-N
InChI=1/C28H28P2/c1-23(29(25-15-7-3-8-16-25)26-17-9-4-10-18-26)24(2)30(27-19-11-5-12-20-27)28-21-13-6-14-22-28/h3-24H,1-2H3/t23-,24-/m0/s1
Key: FWXAUDSWDBGCMN-ZEQRLZLVBA
Properties Molecular formula C28H28P2 Molar mass 426.47 g/mol Appearance White powder Melting point 104–109 °C
Hazards EU classification Irritant (XI) R-phrases R36/37/38 S-phrases S26 S37/39 (verify) (what is:
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)Infobox references Chiraphos is a chiral diphosphine employed as a ligand in organometallic chemistry. This bidentate ligand chelates metals via the two phosphine groups. Its name is derived from its description — being both chiral and a phosphine. Chiraphos is available in two enantiomeric forms, S,S and R,R, each with C2 symmetry.
Preparation
Chiraphos is prepared from S,S or R,R-2,3-butanediol, which are derived from commercially available S,S or R,R-tartaric acid; the technique of using cheaply available enantiopure starting materials is known as chiral pool synthesis. The diol is tosylated and then the ditosylate is treated with lithium diphenylphosphide.[1] The ligand was an important demonstration of how the conformation of the chelate ring can affect asymmetric induction by a metal catalyst. Prior to this work, in most chiral phosphines, e.g., DIPAMP, phosphorus was the stereogenic center.
References
- ^ M. D. Fryzuk, B. Bosnich (1977). "Asymmetric synthesis. Production of optically active amino acids by catalytic hydrogenation". J. Am. Chem. Soc. 99 (19): 6262–6267. doi:10.1021/ja00461a014. PMID 893889.
- This article incorporates information from the revision as of 12:39, 21 June 2008 (UTC) of the equivalent article on the German Wikipedia.
Categories:- Bisphosphanes
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