Abstract10‐Hydroxy and 10‐aminoundecanoic acids are conveniently prepared by solvomercuration‐demercuration of 10‐undecenoic acid using THF‐water and acetonitrile as nucleophilic solvents respectively. BF3‐catalysed dimethyl sulphoxide oxidation of its methyl epoxide resulted in the formation of methyl 10‐keto‐11‐hydroxyundecanoate. Thus in the case of a terminal olefinic acid only one out of the two isomeric products is formed according to Markonikov direction in th