The Favorskii rearrangement of α-chloro β-keto sulfones, which are easily synthesized from aldehydes and ketones, with amines gives β-sulfonyl amides in good yield. These β-sulfonyl amides are converted to amides and α,β-unsaturated amides by reduction or elimination of the sulfonyl group.
Favorskii Rearrangement and Carbon–Carbon Bond-Cleavage of<i>α</i>-Chloro-<i>α</i>-sulfonyl Ketones: A Synthesis of Carboxylic Acids and Their Derivatives from Aldehydes and Ketones
derivatives from aldehydes and ketones via α-chloro-α-sulfonyl ketones is described. Acyclic α-chloro-α-sulfonyl ketones were synthesized from aldehydes and 1-chloroalkyl p-tolyl sulfoxides with carbon–carbon coupling in good overall yields. Cyclic α-chloro-α-sulfonyl ketones were synthesized from cyclic ketones in three steps in high overall yields. The Favorskiirearrangement of both acyclic- and cyclic