A methodology for the direct introduction of the trifluoromethyl group on to indole scaffolds is presented. The procedure involves the use of sodium trifluoromethylsulfinate (Langlois reagent) as the source of the trifluoromethyl radical, and is performed photochemically with 2-tert-butylanthraquinone as a photocatalyst. The reaction has also been probed computationally. Reaction kinetics and molecular orbital analyses from our quantum chemical computations successfully predict and rationalize the formation of the experimentally observed product and, in the case of 1-methylbenzimidazole, even reproduce the same qualitative trends in regioisomer preference.
- Density functional calculations
- Langlois reagent