Triethyl phosphonoacetate

Description

Triethyl phosphonoacetate is a reagent for organic synthesis used in the Horner-Wadsworth-Emmons reaction (HWE) or the Horner-Emmons modification. This compound can be added dropwise to sodium methoxide solution to prepare a phosphonate anion. It has an acidic proton that can easily be abstracted by a weak base. When used in an HWE reaction with a carbonyl, the resulting alkene formed is usually the E alkene and is generated with excellent regioselectivity. It can synthesize β-Keto Phosphonates via an acylation reaction of triethyl phosphonoacetate with carboxylic acid chlorides in the presence of magnesium chloride-triethylamine followed by decarbethoxylation. Acylation of triethyl phosphonoacetate using magnesium ethoxide affords acyl phosphonoacetates, which, on treatment with catalytic p-TsOH in water, are converted into 2-aryl-2-oxoalkylphosphonates[1-2].

Chemical properties

Triethyl phosphonoacetate is Colorless to light yellow liqui

The Uses of Triethyl phosphonoacetate

Triethyl phosphonoacetate is used for Horner-Emmons modification.

The Uses of Triethyl phosphonoacetate

Triethyl phosphonoacetate serves as a reactant used in Horner-Wadsworth-Emmons reactions, Tsuji-Trost type reactions, Intramolecular Heck-type cyclization and isomerizations and Intramolecular aryne-ene reactions. In Horner-Wadsworth-Emmons reaction, it is utilized as a reagent to prepare chiral 2-methylcyclopropanecarboxylic acid from (S)-propylene oxide.

Purification Methods

Purify it by fractional distillation, preferably in vacuo. NMR has P resonance at 19.5 relative to orthophosphate. [Kosolapoff & Powell J Am Chem Soc 68 1103 1946, Kosolapoff & Powell J Am Chem Soc 72 4198 1950, Speziale & Freeman J Org Chem 23 1586 1958, Beilstein 4 IV 3613.]

References

[1] D. Kim, D. Rhie, M. S. Kong. “A New Synthesis of 2-Aryl-2-Oxoalkylphosphonates from Triethyl Phosphonoacetate.” Synthetic Communications 25 1 (1995): 2865–2869.
[2] D. Kim, T. Kim, M. S. Kong. “A Practical Synthesis of β-Keto Phosphonates from Triethyl Phosphonoacetate.” Synthetic Communications 32 1 (1996): 2487–2496.