Simple, one step functionalizations of C-H and C-F bonds have a range of applications, from commodity chemical synthesis to pharmaceuticals. Efforts in our group have focused on transitioning such activations to more abundant first row metals, specifically Co. In this poster, we present our strategy of generating Co(I) fragments in situ for C-H ad C-X bond activation. Using magnesium as a mild reductant, we have found [Cp*CoCl]2 is an excellent precatalyst for transfer dehydrogenation of silyl protected amines at mild temperatures (70 �C) over a few hours. The mechanism of the reaction is similar to that observed with known, isolable Cp*Co(I) sources. However, the presence of cobalt hydrides is observed with the in situ systems, based on the use of labeled olefin probes. The Cp*Co(II) precatalysts can even be used in the catalytic defluorination of perfluorodecalin, though extended heating and reaction times are required for reasonable conversions. Substrate scope of this C-F activation and dehydrofluorination will be presented along with attempts to isolate potential intermediates in the chemistry. Efforts to use air stable Co catalysts, to make the desired C-H and C-F bond functionalizations more amenable to a wider audience of chemists, will also be discussed.

Activation of C-H and C-F bonds by in situ generated Cp*Co(I) fragments

243rd National Meeting (2012)

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