Arylmagnesiation of Alkynes Catalyzed by Iron and Copper Complexes

Significance

This method represents an example for a promising concept of metal-catalyzed reactions: cooperative bimetallic catalysis. Besides being of interest from a mechanistic point of view, this reaction offers significant advantages for the synthesis of complex molecules. So far, the addition of aryl metals to deactivated internal alkynes remains a very challenging task, which was not solved for dialkyl-substituted derivatives. Herein, the ArMgX addition to arylalkyl- and silyl­alkyl-substituted acetylenes proceeds with high regioselectivity. Trapping of the formed vinylmagnesium species with electrophiles is also possible and affords the corresponding products in good yields. The metal salts used as catalysts, namely Fe(acac)₃ and CuBr, are inexpensive and non-toxic.