Carbon–carbon bond fission on oxidation of primary alcohols to carboxylic acids

α-Carbon–carbon bond cleavage is shown to be a general side reaction accompanying the oxidation of unbranched primary alcohols to the corresponding carboxylic acids using HNO3, CrO3/H2SO4/H2O/acetone, CrO3/CH3COOH, PDC/DMF, H5IO6/CrO3, KMnO4/H+, KMnO4/HO−, NiCl2/NaClO, TEMPO/PhI(OAc)2. Therefore, the product formed is always contaminated with a carboxylic acid containing one carbon atom less. Systems such as PhI(OAc)2/TEMPO or H5IO6/CrO3/CH3CN reduce to a minimum the content of this impurity. Temperature, the order of reagent addition, and additives such as oxalic acid or cerium salts produce a profound effect on the formation of the undesirable impurity during the Jones oxidation of primary alcohols.