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 CF(3) group from the Cu complex to the propargylic substrate.