Enhancing the nucleophilicity of aluminyl anions: targeting selective C-H activation

Anionic aluminium(i) complexes, or aluminyl anions, are a recently discovered class of main group compounds that can C-H activate simple aromatic molecules. However, functional group tolerance remains an issue, with the activation of functionalised arenes often favouring more kinetically accessible side reactions (e.g. C-O/C-F activation) over the desired C-H activation. Here, we report a new, electron-rich potassium aluminyl complex, which by DFT has been calculated to be the most nucleophilic diamido aluminyl anion reported to date. The anion shows unprecedented rates of reaction towards the C-H activation of arenes, achieving the C-H activation of stoichiometric benzene in seconds at room temperature. Furthermore, the C-H activation is selective even in a range of functionalised arenes, including those with C-O and C-F bonds.