Trifluoromethylation of Propargylic Halides and Trifluoroacetates Using (Ph₃P)₃Cu(CF₃) Reagent

A copper-mediated trifluoromethylation of propargylic halides and trifluoroacetates was performed with high allenyl or propargyl selectivity. The reaction proceeds smoothly with aliphatic and aromatic substituents bearing either electron-withdrawing or -supplying groups. Preliminary mechanistic results indicate an ionic mechanism involving nucleophilic transfer of the CF₃ group from the Cu complex to the propargylic substrate