Homocoupling of aryl halides promoted by an NiCl2/bpy/Mg system in DMF

Homocoupling of aryl halides (2 ArX → Ar―Ar) promoted by NiCl 2 /2,2′‐bipyridine (bpy)/Mg mixtures in DMF has been studied. Mixtures of NiCl 2 , bpy and Mg in DMF promoted homocoupling of aryl halides such as phenyl bromide and p ‐tolyl bromide to give the coupling products in good (e.g. approximately 60–75%) yields, and the homocoupling products were easily isolated from the reaction mixtures. Application of this homocoupling to dibromo‐aromatic compounds (Br–arylene–Br: 2,5‐dibromopyridine, 2,7‐dibromo‐9.9‐dioctylfluorene and 2,7‐dibromo‐9,10‐dioctyl‐9,10‐dihydrophenanthrene) gave the corresponding π‐conjugated polymers, –(arylene) n –, in good yields. Organometallic processes for the homocoupling are discussed. Copyright © 2014 John Wiley & Sons, Ltd.