Regio- and Stereoselective Allylic Trifluoromethylation and Fluorination using CuCF₃ and CuF Reagents

Copper-mediated trifluoromethylation of allylic chlorides and trifluoroacetates was performed using a convenient Cu–CF₃ reagent. The reaction is suitable for selective synthesis of allyl trifluoromethyl species. Mechanistic studies indicate that the reaction proceeds via a nucleophilic substitution mechanism involving allyl copper intermediates. The analogous Cu–F reagent was suitable for fluorination of allyl chlorides. Stereodefined cyclic substrates reacted regio- and stereoselectively