Iron-Catalyzed Arylmagnesiation of Aryl(alkyl)acetylenes in the Presence of an N-Heterocyclic Carbene Ligand

Addition of arylmagnesium bromides to aryl(alkyl)acetylenes proceeded in the presence of an iron catalyst and a N-heterocyclic carbene ligand to give high yields of the corresponding alkenylmagnesium reagents, which were transformed into tetrasubstituted alkenes by subsequent treatment with electrophiles. [reaction: see text]