Synthesis, mechanism of formation, and catalytic activity of Xantphos nickel π-complexes

Abstract

A general synthetic route to the first Xantphos nickel alkyne and alkene complexes has been discovered. Various Ni π-complexes were prepared and characterized. NMR experiments indicate benzonitrile undergoes ligand exchange with a Xantphos ligand of (Xant)₂Ni, a compound that was previously believed to be unreactive. The Ni π-complexes were also shown to be catalytically competent in cross coupling and cycloaddition reactions. (Xant)₂Ni is also catalytically active for these reactions when activated by a nitrile or coordinating solvent.