Trifluoroethanol promoted formal nucleophilic substitution of indol-2-yl diaryl methanol for the synthesis of tetraarylmethanes.

The synthesis of tetraarylmethanes has long been a challenge in the field of synthetic chemistry. In this study, a series of tetraarylmethanes were successfully synthesized through the formal nucleophilic substitution reaction of indol-2-yl diaryl methanol catalyzed by Brønsted acid. The key success of this study lies in suppressing the influence of water molecules by forming hydrogen bonds with the TFE solvent.

Metal-Free C(sp)-H Bond Arylation of 3-Methylindole Derivatives via 3-Indole Imine Methides.

Direct arylation of the benzylic C(sp)-H bond is one of the most straightforward strategies for the construction of multi-aryl methanes, owing to the extraordinary step and atom economy. In this paper, we developed the first metal-free arylation of the C(sp)-H bond in 3-methylindoles, thereby providing rapid access to a range of diaryl- and triarylmethanes with two indole rings. Mechanistically, 3-indole imine methide serves as the key intermediate.