The invention relates to a method for the enantioselective preparation of substituted sulphoxide derivatives. The method comprises carrying out an enantioselective oxidation of a sulphide of general formula (I): A-CH2—S—B (I), where A=a variously-substituted pyridyl nucleus and B=a heterocyclic group with a benzimidazole or imidazopyrdyl nucleus, by means of an oxidising agent in the presence of a catalyst based on tungsten or vanadium and a chiral ligand, followed, where necessary, by salt formation with a base to give the sulphoxide: A-CH2—SO—B (Ia). The above is of application to the enantioselective preparation of compounds such as the enantiomers of tenatoprazole and other comparable sulphoxides.