Monoesterfication of Alkylphosphonic Acids by DCC-Celite

Significance

A solvent-free synthesis of O-alkyl hydrogen alkyl phosphonates was described. Thus, the reaction of alkylphosphonic acids and alcohols (1 mol equiv) with DCC-Celite (2 mol equiv) was carried out at room temperature to 60 °C to give the corresponding monoesters in 80-92% yield (15 examples). The monoesterification with primary and secondary alcohols was completed within 30-45 and 45-60 min, respectively, while tertiary alcohols did not react with alkylphosphonic acids under similar conditions.