 In this reaction step the oxime is converted into the nitrile with simultaneous conversion of all the alcohol groups to acetate groups.In the final step sodium methoxide in methanol is added, leading to removal of all the acetate groups and ejection of the nitrile group and collapse of the second carbon from a tetrahedral structure to an aldehyde.In a variation, the Ruff–Fenton degradation (Otto Ruff 1898, H.J.H.