Chiraphos

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Chiraphos
Chiraphos.png
Identifiers
CAS number 74839-84-2 (R,R-Enantiomer) YesY, 64896-28-2 (S, S-Enantiomer)
PubChem 10113249
ChemSpider 8288775 YesY
Jmol-3D images Image 1
Properties
Molecular formula C28H28P2
Molar mass 426.47 g/mol
Appearance White powder
Melting point 104 to 109 °C (219 to 228 °F; 377 to 382 K)
Hazards
EU classification Irritant (XI)
R-phrases R36/37/38
S-phrases S26 S37/39
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
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[edit]

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.

ChiraphosSyn.png

References[edit]

  1. ^ 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.