:Chiraphos
{{chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 428730398
| ImageFile = Chiraphos.svg
| ImageFileL2 = Chiraphos-3D-balls-by-AHRLS-2012.png
| ImageSizeL2 = 140
| ImageFileR2 = Chiraphos-3D-sticks-by-AHRLS-2012.png
| ImageSizeR2 = 140
| PIN = rel-[(2R,3R)-Butane-2,3-diyl]bis(diphenylphosphane)
| OtherNames = {{ubl|(2S,3S)-(–)-Bis(diphenylphosphino)butane|(2R,3R)-(+)-Bis(diphenylphosphino)butane}}
|Section1={{Chembox Identifiers
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 8288775
| PubChem = 10113249
| 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
| InChIKey = FWXAUDSWDBGCMN-ZEQRLZLVBA
| SMILES = P(c1ccccc1)(c2ccccc2)[C@H]([C@@H](P(c3ccccc3)c4ccccc4)C)C
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 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
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = FWXAUDSWDBGCMN-ZEQRLZLVSA-N
| CASNo_Ref = {{cascite|correct|??}}
| CASNo = 74839-84-2
| CASNo_Comment = (R,R)
| CASNo1_Ref = {{cascite|correct|??}}
| CASNo1 = 64896-28-2
| CASNo1_Comment = (S,S)
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 1T086B9Q1J
| UNII_Comment = (R,R)
| UNII1_Ref = {{fdacite|correct|FDA}}
| UNII1 = 6QR78GZL9B
| UNII1_Comment = (S,S)
}}
|Section2={{Chembox Properties
| Formula = C28H28P2
| Appearance = White powder
| MolarMass = 426.47 g/mol
| MeltingPtC = 104 to 109
| MeltingPt_notes =
}}
|Section3={{Chembox Hazards
| GHSPictograms = {{GHS07}}
| GHSSignalWord = Warning
| HPhrases = {{H-phrases|315|319|335}}
| PPhrases = {{P-phrases|261|264|271|280|302+352|304+340|305+351+338|312|321|332+313|337+313|362|403+233|405|501}}
}}
}}
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. As a C2-symmetric ligand, 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.{{cite journal|last1=Fryzuk|first1=M. D.|last2=Bosnich|first2=B.|authorlink2=Brice Bosnich|title=Asymmetric synthesis. Production of optically active amino acids by catalytic hydrogenation|journal=Journal of the American Chemical Society|volume=99|issue=19|year=1977|pages=6262–6267|pmid=893889|doi=10.1021/ja00461a014}} 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.
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