The Lemieux-Johnson oxidation is a chemical reaction named after its discoverers, R. U. Lemieux and W. S. Johnson, who published it in 1956.[1] It involves the oxidation of an olefin to produce a 1,2-diol or two aldehydes. It is a two-step reaction, the first step consisting of the dihydroxylation of the carbon-carbon double bond by the Lemieux-Johnson reagent (sodium periodate-osmium tetroxide) and the second being the cleavage of the carbon-carbon single bond. The Lemieux-Johnson reaction ceases at the aldehydic stage of oxidation and therefore produces the same results as ozonolysis and subsequent reductive cleavage.