The Willgerodt rearrangement or Willgerodt reaction is an organic reaction converting an aryl alkyl ketone, alkyne, or alkene to the corresponding amide by reaction with ammonium polysulfide, named after Conrad Willgerodt.[1][2][3][4] The formation of the corresponding carboxylic acid is a side reaction resulting from hydrolysis of the amide. When the alkyl group is an aliphatic chain (n typically 0 to 5), multiple reactions take place with the amide group always ending up at the terminal end. The net effect is thus migration of the carbonyl group to the end of the chain and oxidation.
The related Willgerodt–Kindler reaction[6] takes place with elemental sulfur and an amine like morpholine. The initial product is a thioamide for example that of acetophenone[7] which can again be hydrolyzed to the amide. The reaction is named after Karl Kindler [de]
^Carmack, Marvin; F. DeTar, DeLos (1946). "The Willgerodt and Kindler Reactions. III. Amides from Acetylenes and Olefins; Studies Relating to the Reaction Mechanisms". Journal of the American Chemical Society. 68 (10): 2029–2033. doi:10.1021/ja01214a048.
^The Willgerodt Reaction. II. A Study of Reaction Conditions with Acetophenone and Other KetonesDeLos F. DeTar and Marvin Carmack J. Am. Chem. Soc.1946, 68(10), 2025 - 2029. (doi:10.1021/ja01214a047)