:PCl₃ + CH₃CHO -> CH₃CH(O^-)This adduct reacts with acetic acid:
: CH₃CH(O^-) + 2 CH₃CO₂H -> CH₃CH(Cl)PO(OH)₂ + 2 CH₃COClThis chloride undergoes dehydrochlorination to afford the target:
:CH₃CH(Cl)PO(OH)₂ -> CH₂=CHPO(OH)₂ + HCl

In the Kinnear-Perren reaction alkylphosphonyl dichlorides and esters are generated by alkylation