A phosphite ester or organophosphite is a type of chemical compound with the general structure P(OR)3. Phosphite esters can be considered as esters of phosphorous acid, H3PO3. A simple phosphite ester is trimethylphosphite, P(OCH3)3. Phosphite esters can be prepared by reacting phosphorus trichloride or phosphorus tribromide with an alcohol and a tertiary amine.
Phosphite esters are used in the Perkow reaction in the formation of vinyl phosphonates and in the Michaelis-Arbuzov reaction to form phosphonates. One other particular use is that of reducing agent. For example triethylphosphite is known to reduce certain hydroperoxides to alcohols formed by autoxidation (scheme 1). In this process the phosphite is converted to a phosphate ester.
This reaction type is also utilized in the Wender Taxol total synthesis.
The compound trimethylolpropane phosphite is a ligand used in organometallic chemistry.