Monosubstituted phosphinic acids are esterified with orthosilicates in excellent yields. Phosphinylidene-containing acids react selectively under these conditions, while disubstituted phosphinic acids and phosphonic acids remain unchanged. One-pot procedures are also described for the preparation of phosphinate esters from an alcohol. This novel method provides a convenient and general alternative to more commonly employed conditions such as diazomethane or carbodiimide.
Orthosilicate-Mediated Esterification of Monosubstituted Phosphinic Acids
I repeated the preparation of substrate 3 as the entry 5 in table 1 followed their protocol. The reaction went smoothly to afford...