Process for the preparation of 2-methoxyimino-2-arylacetic esters of formula (I) in which R is C.sub.1 -C.sub.12 alkyl, which comprises reacting an appropriately substituted boronic acid of general formula (II) or the trimeric form (lII) herein, which is in equilibrium with it, in the presence of a Pd catalyst, with a methoxyiminoacetic ester of formula (IV) in which R is C.sub.1 -C.sub.12 alkyl and X is a leaving group. According to a further process variant, in principle the groups which split off the two reactants may change places. The process can be applied not only to phenyl derivatives but also to larger ring systems (naphthyl, pyridyl, heterocycles).