Effect of halogenation reagents on halocyclization and Overman rearrangement of allylic trichloroacetimidates

Electrophilic halogen can promote either halocyclization or Overman rearrangement of allylic trichloroacetimidates. We found that the chemoselectivity was dependent on the nature of the halogenation reagents for primary allylic trichloroacetimidates. A one-pot procedure was developed for the preparation of allylic trichloroacetamides directly from allylic alcohols at room temperature.