(S)-iPr-PHOX

(S)-iPr-PHOX, or (S)-2-[2-(diphenylphosphino)phenyl]-4-isopropyl-4,5-dihydrooxazole, is a chiral, bidentate, ligand derived from the amino alcohol valinol. It is part of a broader class of phosphinooxazolines ligands and has found application in asymmetric catalysis.

(S)-iPr-PHOX

Names
Preferred IUPAC name (4S)-2-[2-(Diphenylphosphanyl)phenyl]-4-(propan-2-yl)-4,5-dihydro-1,3-oxazole
Identifiers
CAS Number	148461-14-7
3D model (JSmol)	Interactive image
ChemSpider	7983538
PubChem CID	9807779
CompTox Dashboard (EPA)	DTXSID60403391
InChI InChI=1S/C24H24NOP/c1-18(2)22-17-26-24(25-22)21-15-9-10-16-23(21)27(19-11-5-3-6-12-19)20-13-7-4-8-14-20/h3-16,18,22H,17H2,1-2H3/t22-/m1/s1 Key: OUQSAXROROGQEE-JOCHJYFZSA-N
SMILES CC(C)[C@H]1COC(=N1)C2=CC=CC=C2P(C3=CC=CC=C3)C4=CC=CC=C4
Properties
Chemical formula	C24H24NOP
Molar mass	373.436 g·mol−1
Appearance	White solid
Melting point	85 to 90 °C (185 to 194 °F; 358 to 363 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Preparation

(S)-iPr-PHOX is prepared using the amino alcohol valinol, which is derived from valine. The phosphine moiety may be introduced first, by a reaction between 2-bromobenzonitrile and chlorodiphenylphosphine; the oxazoline ring is then formed in a Witte Seeliger reaction. This yields an air stable zinc complex which must be treated with bipyridine in order to obtain the free ligand. Synthesis is performed under argon or nitrogen to avoid contact with air, however the final product is not air sensitive.

Uses

Iridium complexes incorporating (S)-iPr-PHOX have been used for asymmetric hydrogenation.^[1]

References

1. Woodmansee, David H.; Pfaltz, Andreas (2011). "Iridium-Catalyzed Asymmetric Hydrogenation of Olefins with Chiral N,P and C,N Ligands". Iridium Catalysis. Topics in Organometallic Chemistry. Vol. 34. p. 31. doi:10.1007/978-3-642-15334-1_3. ISBN 978-3-642-15333-4.