{{chembox | verifiedrevid = 409102763 | ImageFile = SPANphos.svg | PIN = (4,4,4′,4′,6,6′-Hexamethyl-3,3′,4,4′-tetrahydro-2,2′-spirobi[<nowiki/>[1]benzopyran]-8,8′-diyl)bis(diphenylphosphane) |Section1 = {{Chembox Identifiers | CASNo = 556797-94-5 | CASNo_Ref = {{Cascite|changed|}} | ChemSpiderID = 57592633 | EC_number = 814-334-7 | PubChem = 12103420 | SMILES = CC1=CC(=C2C(=C1)C(CC3(O2)CC(C4=CC(=CC(=C4O3)P(C5=CC=CC=C5)C6=CC=CC=C6)C)(C)C)(C)C)P(C7=CC=CC=C7)C8=CC=CC=C8 | InChIKey = RQMTZMWXNZQOPD-UHFFFAOYSA-N | InChI = 1S/C47H46O2P2/c1-33-27-39-43(41(29-33)50(35-19-11-7-12-20-35)36-21-13-8-14-22-36)48-47(31-45(39,3)4)32-46(5,6)40-28-34(2)30-42(44(40)49-47)51(37-23-15-9-16-24-37)38-25-17-10-18-26-38/h7-30H,31-32H2,1-6H3 }} |Section2 = {{Chembox Properties | Formula = C<sub>47</sub>H<sub>46</sub>O<sub>2</sub>P<sub>2</sub> | MolarMass = 704.814 g/mol }} }}
'''SPANphos''' is an organophosphorus compound used as a ligand in organometallic and coordination chemistry. The compound is a rare example of a trans-spanning ligand and rigidly links mutually trans coordination sites. By virtue of its C<sub>2</sub>-symmetric backbone, SPANphos forms a chiral cavity over the face of a square planar complexes, e.g. in MCl<sub>2</sub>(SPANphos) (M = Pd, Pt).thumb|left|144px|Structure of PtCl<sub>2</sub>(SPANphos)<ref name=Freixa/>
==Synthesis== SPANphos can be prepared synthesized from relatively inexpensive reagents. In the first step 4,4,4',4',6,6'-hexamethyl-2,2'-spirobichromane is prepared via an acid-catalyzed reaction of p-cresol and acetone. The resultant spirocycle is halogenated with N-bromosuccinimide followed by lithium-bromide exchange using n-BuLi. Treatment of the resulting dilithio compound with chlorodiphenylphosphine completes the synthesis.<ref name=Freixa>{{cite journal | author = Z. Freixa, M. S. Beentjes, G. D. Batema, C. B. Dieleman, G. P. F. van Strijdonck, J. N. H. Reek, P. C. J. Kamer, J. Fraanje, K. Goubitz and P. W. N. M. van Leeuwen | title = SPANphos: A ''C''<SUB>2</SUB>-Symmetric ''trans''-Coordinating Diphosphane Ligand | journal = Angewandte Chemie International Edition | year = 2003 | volume = 42 | issue = 11 | pages = 1322–1325 |doi = 10.1002/anie.200390330 | pmid = 12645065}}</ref> :[[File:SPANphosPrep.png|thumb|center|344px|Preparation of SPANphos from p-cresol]]
==References== <references/>
Category:Diphosphines Category:Benzopyrans Category:Spiro compounds