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.