a site of unsaturation. Oxygen and nitrogen atoms also promote fragmentation through the formation of ketones and imines respectively. Sulfur is also capable of promoting fragmentation, albeit at a longer range than oxygen or nitrogen. Silicon is capable of directing the fragmentation through the beta-silicon effect. The carbocation intermediate in this reaction is intercepted by nucleophilic fluoride from diethylaminosulfur trifluoride (DAST): Semmler–Wolff reaction The oxime of cyclohexenone with acid forms aniline in a dehydration – aromatization reaction called the Semmler–Wolff reaction or Wolff aromatization The mechanism can be shown as below: The reaction is intrinsically a special case of Beckmann rearrangement combined with neighbouring group participation. Applications in drug synthesis An industrial synthesis of paracetamol developed by Hoechst–Celanese involves the conversion of a methyl ketone to an acetanilide via a Beckmann rearrangement. The thermal rearrangement that occurs in the synthesis of ketamine was claimed to be a Beckmann rearrangement according to: url. See also Curtius rearrangement Dakin reaction Schmidt reaction Stieglitz rearrangement Lossen rearrangement References External links Animation of the Beckmann rearrangement Animation of the Beckmann rearrangement (caprolactam) Rearrangement reactions Nitrogen heterocycle forming reactions Ring expansion reactions Name reactions Amide synthesis reactions