The invention relates to a process for the manufacture of α,α-branched carboxylic acids vinyl esters comprising the following steps: isomerising and converting an olefin feed with CO and water under Koch reaction conditions to make an acid with a ratio of Non Blocking isomers (NB) versus Blocking isomers (B) of NB/B above 1.5, wherein a blocking isomer has always a tertiary carbon atom in alpha position of the carboxylic acid and in the beta position of the carboxylic acid, whereas a non-blocking isomer has primary carbon atoms in the beta position of the carboxylic acid converting the resulting acid into a vinyl ester.