{{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''-[(2''R'',3''R'')-Butane-2,3-diyl]bis(diphenylphosphane) | OtherNames = {{ubl|(2''S'',3''S'')-(–)-Bis(diphenylphosphino)butane|(2''R'',3''R'')-(+)-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 = C<sub>28</sub>H<sub>28</sub>P<sub>2</sub> | 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 &mdash; being both ''chiral'' and a ''phosphine''. As a C<sub>2</sub>-symmetric ligand, chiraphos is available in two enantiomeric forms, ''S'',''S'' and ''R'',''R'', each with C<sub>2</sub> symmetry.<!--meso is not chiraphos-->

==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.<ref name=FryzukBosnich1977>{{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}}</ref> 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.<!--I dont think that this ligand is used for anything anymore-->

::330px<!--I think that the rxn goes with double inversion-->

==References== <references/>

Category:Diphosphines Category:Phenyl compounds