A new efficient catalytic system for the chemoselective cobalt-catalyzed cross-coupling of aryl Grignard reagents with primary and secondary alkyl bromides.

The cobalt-catalyzed alkylation of aromatic Grignard reagents is performed in good yields by using a new simple and efficient catalytic system: CoCl(2)/TMEDA (1:1). Primary and secondary cyclic or acyclic alkyl bromides were used successfully. The reaction is highly chemoselective since ester, amide, and keto groups are tolerated. The procedure is inexpensive and very easy to carry out on a larger scale.