Phosphonite Explained

In organic chemistry, phosphonites are organophosphorus compounds with the formula P(OR)₂R. They are found in some pesticides and are used as ligands.^[1]

Preparation

Although they are derivatives of phosphonous acid (RP(OH)₂), they are not prepared from such precursors. Phosphonites are prepared by alcoholysis of organophosphinous chlorides. For example, treatment of dichlorophenylphosphine with methanol and base gives dimethyl phenylphosphonite:

Cl₂PPh + 2 CH₃OH → (CH₃O)₂PPh + 2 HCl

Reactions

Oxidation of phosphonites gives phosphonates:

2 P(OR)₂R + O₂ → 2 OP(OR)₂R

Phosphonites can function as ligands in homogeneous catalysis.^[2]

References

1. D. E. C. Corbridge "Phosphorus: An Outline of its Chemistry, Biochemistry, and Technology" 5th Edition Elsevier: Amsterdam 1995. .
2. T. V. (Babu) Rajanbabu “Phosphinite and Phosphonite Ligands” in Phosphorus(III) Ligands in Homogeneous Catalysis: Design and Synthesis Paul C. J. Kamer and Piet W. N. M. van Leeuwen, Eds., John Wiley & Sons 2012.