Investigations in the reactivity of hypervalent trifluoromethyl iodanes towards low-valent cobalt and nickel complexes - a contribution to the insight into metal-mediated electrophilic trifluoromethylations

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Hypervalent trifluoromethyl iodane(I) reagents ("Togni's reagents") are suitable for selective electrophilic trifluoromethylation of numerous substrates such as alcohols, thiols and various N and C nucleophiles. While the iodanes are activated for the mentioned reactions by lewis-acid (electrophilic) metal compounds, their behavior against nucleophilic metal compounds is rarely investigated so far. Within the scope of this project the reactivity of a carboxy iodane and a alkoxy iodane towards a series of simple low-valent CO and PPh3 complexes of cobalt and nickel is explored systematically. Thereby an oxidative trifluoromethylation of the metal atom is expected (e.g. M(0) to M(II)-CF3), implying a formal "umpolung" CF3+/CF3-. The focus of the research is how the properties and subsequent reactions of the products depend on metal, oxidation state, ligands and used iodane reagent. The so-gained findings can provide a basis for the development of new trifluoromethylation reactions and catalysts.