Organocopper(ii) complexes: new catalysts for carbon–carbon bond formation via electrochemical atom transfer radical addition (eATRA)

Organocopper(ii) complexes are a rarity while organocopper(i) complexes are commonplace in chemical synthesis. In the course of building a strategy to generate organocopper(ii) species utilizing electrochemistry, a method to form compounds with Cu^II–C bonds was discovered, that demonstrated remarkably potent reactivity towards different functionalized alkenes under catalytic control. The role of the organocopper(ii) complex is to act as a source of masked radicals (in this case ˙CH₂CN) that react with an alkene to generate the corresponding γ-halonitrile in good yields through atom transfer radical addition (ATRA) to various alkenes. The organocopper(ii) complexes can be continuously regenerated electrochemically for ATRA (eATRA), which proceeds at room temperature, under low Cu loadings (1–10 mol%) and with the possibility of Cu-catalyst recovery.

Electrochemical generation of a novel organocopper(ii) complex offers a new way to carry out atom transfer radical addition to alkenes under mild conditions with high yields and low catalyst loadings.