Characterization of the reactivity of well-defined arylcopper(III) species

Copper salts are desirable catalysts for carbon--nitrogen and carbon--oxygen bond forming reactions due to their low cost and high efficacy in these reactions. Carbon--heteroatom bond formation resulting from reductive elimination from an organometallic copper(III) species is commonly invoked as a key step in catalytic reactions, including the century-old Ullmann reactions. Well-defined examples of such reactions have never been observed. In this work, we have demonstrated the role of arylcopper(III) intermediates using a well-defined arylcopper(III) complex and characterizing its reaction with a broad variety of nitrogen and oxygen nucleophiles. An unusual formally trans intramolecular reductive elimination of the ligand from the copper(III) center was discovered and the mechanism of this reaction has also been elucidated. Finally, studies on the arylcopper(III) species enabled us to use the ligand from the complex in a model study of C--H functionalization and activation with oxygen and copper. The crucial role of organocopper(III) species in carbon--heteroatom bond forming reactions has been demonstrated in this work.