Ruthenium(II)-Catalyzed Direct C-H Arylation of Indoles with Arylsilanes in Water.

The ruthenium(II)-catalyzed, heteroatom-directed C-H arylation of indoles with arylsilanes in water has been developed. The method represents the first example of a ruthenium(II)-catalyzed oxidative C-H arylation in water/aqueous media as a sustainable solvent for C-H functionalization. The reaction enables the synthesis of a wide range of indoles with exquisite selectivity for arylation at the C-2 position. Preliminary mechanistic studies indicate reversibility of the C-H ruthenation step under the developed reaction conditions.