The coupling of primary and secondary unactivated alkyl bromides with alkyl-Grignard reagents was performed in good yields under mild conditions by using a new catalytic system: consisting of cobalt chloride and tetramethylethylenediamine (CoCl2⋅2 LiI, 4 TMEDA). The reaction is very chemoselective since ketone, ester and nitrile functions are tolerated.