Oxidant-Free Au(I)-Catalyzed Halide Exchange and Csp2-O Bond Forming Reactions

Au has been demonstrated to mediate a number of organic transformations through the utilization of its pi Lewis acid character, Au(I)/Au(III) redox properties or a combination of both. As a result of the high oxidation potential of the Au(I)/Au(III) couple, redox catalysis involving Au typically requires the use of a strong external oxidant. This study demonstrates unusual external oxidant-free Au(I)-catalyzed halide exchange (including fluorination) and C-sp2-O bond formation reactions utilizing a model aryl halide macrocyclic substrate. Additionally, the halide exchange and C-sp2-O coupling reactivity could also be extrapolated to substrates bearing a single chelating group, providing further insight into the reaction mechanism. This work provides the first examples of external oxidant-free Au(I)-catalyzed carbon heteroatom cross-coupling reactions.