The invention relates to a method for producing mono-carboxy-functionalized dialkylphosphinic acids, esters and salts using a vinyl ester of a carboxylic acid. The method is characterized by the following steps: a) reacting a phosphinic acid source (I) with olefins (IV) in the presence of a catalyst A to give an alkylphosphinic acid, the salt or the ester (II) thereof, b) reacting the alkylphosphinic acid so obtained, the salt or the ester (II) thereof with a vinyl ester of a carboxylic acid of formula (V) in the presence of a catalyst B to give a mono-functionalized dialkylphosphinic acid derivative (VI) and c) reacting the mono-functionalized dialkylphosphinic acid derivative (VI) so obtained in the presence of a catalyst C to give a mono-functionalized dialkylphosphinic acid derivative (VII) and d) reacting the mono-functionalized dialkylphosphinic acid derivative (VII); with an oxidant or in the presence of a catalyst D to give a mono-carboxy-functionalized dialkylphosphinic acid derivative (III).