What is "phanephos"

Phanephos is an organophosphorus compound with the chemical formula (CH)(CHPPh) (Ph = CH). It is a white solid that is soluble in organic solvents. It is an example of a chiral diphosphine used in asymmetric hydrogenation. Many substituents have been introduced in place of the phenyl groups, e.g., i-Pr, CH, etc and a variety of chiral phosphine ligands have been reported in asymmetric catalysis since the 1960s.