Electrochemical cross-coupling between 2-halopyridines and aryl or heteroaryl halides catalysed by nickel-2,2'-bipyridine complexes

2-Arylpyridines can be obtained in good to high yields by electrochemical reductin using the sacrificial anode process and catalysis by nickel-2,2'-bipyridine (bpy) complexes. In a first approach functionalized arylzinc species are prepared in DMF as solvent by electrolytic reduction of the corresponding aryl-bromides or -chlorides in the presence of ZnBr₂ and Ni(II)-bpy complexes and then coupled with 2-chloropyridine. In a second approach the cross-coupling occurs from the electrochemical reduction of a stoichiometric mixture of an aryl halide and 2-halopyridine in DMF in the presence of NiBr₂bpy as catalyst.