Desulfonylation of Amides using Tributyltin Hydride, Samarium Diiodide or Zinc/Titanium Tetrachloride. A Comparison of Methods

Deprotection of N-sulfonylated amides can be achieved by reaction with Bu3SnH, SmI2 or TiCl4/Zn. All three methods gave good yields (typically >60%) when using N-benzoyl or related amides while the corresponding N-acetyl derivatives proved to be inert to deprotection under the same reaction conditions. The mechanistic implications of this are discussed.