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. (C) 2000 Elsevier Science Ltd. All rights reserved.