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 C2-symmetric backbone, SPANphos forms a chiral cavity over the face of a square planar complexes, e.g. in MCl2(SPANphos) (M = Pd, Pt).SPANphos can be prepared synthesized from relatively inexpensive reagents.

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.