Direct Monoalkylation of Alkyl Phosphinates to Access H-Phosphinic Acid Esters

Simple alkyl phosphinates prepared by the silicate esterification method can be alkylated under Barbier-like conditions with butyl lithium at -78 °C followed by warming to room temperature. The method is limited to the more reactive electrophile such as allylic bromides and alkyl iodides. With these electrophiles good yields of H-phosphinic acid esters are generally obtained in a straightforward manner.