Phosphorochloridite

In chemistry, phosphorochloridites are a class of organophosphorus compound with the formula (RO)₂PCl (R = organic substituent). They are pyramidal in shape, akin to regular phosphites (P(OR)₃). They are usually colorless and sensitive toward hydrolysis and, to some extent, oxidation to the corresponding phosphorochloridates ((RO)₂P(O)Cl).

Synthesis and reactions

Structure of 2,2'-biphenylene phosphorochloridite.

Phosphorochloridites are produced by partial alcoholysis of phosphorus trichloride, which proceeds stepwise:^[1]

PCl₃ + ROH → HCl + (RO)PCl₂ (phosphochloridite)

(RO)PCl₂ + ROH → HCl + (RO)₂PCl (phosphodichloridite)

(RO)₂PCl + ROH → HCl + (RO)₃P (phosphite)

These reactions are readily controlled with aromatic diols, such as binaphthol and 2,2'-biphenol.

Phosphorochloridites are precursors to diphosphite ligands. When combined with rhodium precursors such as Rh(acac)(CO)₂, these diphosphite ligands afford catalysts that are used industrially for the hydroformylation of alkenes.^[2] it and related ligands have become popular in hydroformylation catalysis.^[3][4]