CoBr2(Bpy): An efficient catalyst for the direct conjugate addition of aryl halides or triflates onto activated olefins

An efficient cobalt-catalyzed method devoted to the direct conjugate addition of functionalized aryl compounds onto Michael acceptors is described. The CoBr₂(2,2′-bipyridine) complex appears to be an extremely suitable catalyst for the activation of a variety of aromatic reagents ranging from halides to triflates functionalized by reactive groups. This procedure allows for the synthesis of compounds resulting from 1,4-addition in good to excellent yields. The versatility of this original process represents a simple alternative to most known methods using organometallic reagents.