Reaction of dimethyl phosphonate with phenylketene dimethyl dithioacetal derivatives have been investigated to prepare s-alkylphosphonates. The addition reactions of phosphonate were accelerated in dithioacetal derivatives in the following order:–SMe<–SOMe<<–SO 2 Me. The reaction of β, β-bis (methylsulfonyl) styrene (7) with dimethyl phosphonate followed by the catalytic reduction afforded dimethyl α-methylbenzylphosphonate in 74% yield from ...