Development of Dual Transition Metal Activation for Methane and Carbon Dioxide and further Processing to Carbamate Formation

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Methane and carbondioxide represent two compounds, which are characterised by their relative inertness to transition metal activation. However, under certain reaction conditions, transformation within the coordination sphere of molecular catalysts can be accomplished. We here propose a novel, economic catalytic synthesis of carbamate fine chemicals from the common bulk materials methane, carbondioxide and amines. The carbamate products represent important and versatile nitrogen sources as applied in organic synthesis for pharmaceutical, medicinal and biological research. Accomplishment of the proposed work should therefore have an impact on various European areas of industrial and academic research. The overall reaction foresees an activation reaction of methane within a transition metal complex, followed by amine coordination and carbondioxide insertion reaction. The carbamate product will be generated by a novel reductive elimination, essentially without any side-product formation. The overall sequence will hence constitute an advantageous process in comparison to the currently employed procedure, which involves phosgene and alcohols.Key issues refer to the development of high selectivity for all steps. This can only be accomplished through appropriately tuning the reactivity of the transition metal centre in combination with a suitable ligand scaffold. The advantage of the presented approach lies in an expected relative ease of independent synthesis for all individual compounds. Hence, it should be possible to optimise each of the individual steps both by theory and by experiment in a complementary fashion. The two groups will then jointly arrive at the establishment of a catalytic cycle for this new transformation.