Xantphos is an organophosphorus compound derived from the heterocycle xanthene

Xanthene

Xanthene is a yellow organic heterocyclic compound. Its chemical formula is 1310. It is soluble in diethyl ether. Its melting point is 101-102 °C and its boiling point is 310-312 °C...

. It is used as a bidentate ligand

Ligand

In coordination chemistry, a ligand is an ion or molecule that binds to a central metal atom to form a coordination complex. The bonding between metal and ligand generally involves formal donation of one or more of the ligand's electron pairs. The nature of metal-ligand bonding can range from...

 and is noteworthy for having a particularly wide bite angle

Bite angle

The bite angle is a geometric parameter used to classify chelating ligands in inorganic and organometallic chemistry. Together with ligand cone angle, this parameter is relevant to diphosphine ligands, which are used in industrial processes such as hydroformylation and hydrocyanation...

. Such ligands are useful in the hydroformylation

Hydroformylation

Hydroformylation, also known as oxo synthesis or oxo process, is an important industrial process for the production of aldehydes from alkenes. This chemical reaction entails the addition of a formyl group and a hydrogen atom to a carbon-carbon double bond...

 of alkene

Alkene

In organic chemistry, an alkene, olefin, or olefine is an unsaturated chemical compound containing at least one carbon-to-carbon double bond...

s. Illustrative of its wide bite angle, it forms both cis and trans adducts of platinum(II) chloride

Platinum(II) chloride

Platinum chloride is the chemical compound PtCl2. It is an important precursor used in the preparation of other platinum compounds. It exists in two crystalline forms, but the main properties are somewhat similar: dark brown, insoluble in water, diamagnetic, and odorless.-Structure:The...

. A related bidentate ligand with a greater bite angle is spanphos

SPANphos

SPANphos is an organophosphorus compound used as a ligand in organometallic and coordination chemistry. This compound is a rare example of a trans-spanning ligand and rigidly links mutually trans coordination sites. By virtue of its chiral backbone that forms a chiral cavity over the face of a...

.

The ligand is prepared by double directed lithiation

Directed ortho metalation

Directed ortho metalation is an adaptation of electrophilic aromatic substitution in which electrophiles attach themselves exclusively to the ortho- position of a direct metalation group or DMG through the intermediary of an aryllithium compound . The DMG interacts with lithium through a hetero atom...

 of 9,9-dimethylxanthene with sec-butyllithium

Sec-Butyllithium

sec-Butyllithium is an organometallic compound with the formula CH3CHLiCH2CH3, abbreviated sec-BuLi or s-BuLi. This chiral organolithium reagent is used as a source of sec-butyl carbanion in organic synthesis....

 followed by treatment with chlorodiphenylphosphine

Chlorodiphenylphosphine

Chlorodiphenylphosphine is an organophosphorus compound with the formula 2PCl, abbreviated Ph2PCl. It is a colourless oily liquid with a pungent odor that is often described as being garlic-like and detectable even in the ppb range. It is useful reagent for introducing the Ph2P group into...

.