Nucleophilic Scandium Carbene Complexes

Using a geminal dianion as precursor, a nucleophilic scandium carbene complex (2) has been synthesized by salt metathesis on ScCl3(THF)(3) in 52% isolated yield. The X-ray structure as well as an NBO analysis points to a double interaction between the carbon and the scandium atoms. Quantification of the electron density donation from the carbon to the metal center, from both sigma and pi symmetry orbitals, predicts a "nucleophilic carbene" behavior. Addition of benzophenone on complex 2 results in the formation of the expected alkene derivative and the trapping of a rare, mu(3)-oxo-Sc species via a "scandia-Wittig" reaction.