Phosphinooxazolines (often abbreviated PHOX) are a class of chiral ligands used in asymmetric catalysis. Their complexes are particularly effective at generating single enatiomers in reactions involving highly symmetric transition states, such as allylic substitutions, which are typically difficult to perform stereoselectively.  The ligands are bidentate and have been shown to be hemilabile
with the softer P‑donor being more firmly bound than the harder N‑donor.