The molecule features a pyramidal phosphorus(III) center bound to three ethoxide groups. Its 31PNMR spectrum features a signal at around +139 ppm vs phosphoric acid standard.
Triethylphosphite is prepared by treating phosphorus trichloride with ethanol in the presence of a base, typically a tertiary amine:[1]
PCl3 + 3 EtOH + 3 R3N → P(OEt)3 + 3 R3NH + 3 Cl−
In the absence of the base, the reaction of ethanol and phosphorus trichloride affords diethylphosphite ((EtO)2P(O)H). Of the many related compounds can be prepared similarly, triisopropyl phosphite is an example (b.p. 43.5 °C/1.0 mm; CAS# 116-17-6).
Reduction/deoxygenation of hydroperoxides to the alcohols can also be effected using triethyl phosphite.[2] This approach can be utilized for carbonyl α-hydroxylation by reacting the enolate with oxygen, producing an α-hydroperoxide which can be reduced by triethyl phosphite to the alcohol.[3] A proposed mechanism is shown below.[4]
Reaction scheme and proposed mechanism for carbonyl α-hydroxylation using oxygen and triethyl phosphite.
Incoordination chemistry and homogeneous catalysis, triethylphosphite finds use as a soft ligand. Its complexes are generally lipophilic and feature metals in low oxidation states. Examples include the colorless complexes FeH2(P(OEt)3)4 and Ni(P(OEt)3)4 (m.p. 108 °C).[5] It also forms a stable complex with copper(I) iodide.[2]
^Gardner, J. N.; Carlon, F. E.; Gnoj, O. (1968). "One-step procedure for the preparation of tertiary α-ketols from the corresponding ketones". The Journal of Organic Chemistry. 33 (8): 3294–3297. doi:10.1021/jo01272a055. PMID5742870.
^Liang, Yu-Feng; Jiao, Ning (2014). "Highly Efficient C–H Hydroxylation of Carbonyl Compounds with Oxygen under Mild Conditions". Angewandte Chemie International Edition. 53 (2): 548–552. doi:10.1002/anie.201308698. PMID24281892.
