Rh(III)-catalyzed synthesis of 1-aminoindole derivatives from 2-acetyl-1-arylhydrazines and diazo compounds in water.

A novel and direct approach to synthesize 1-aminoindole derivatives by Rh(iii)-catalyzed cyclization of 2-acetyl-1-arylhydrazines with diazo compounds via aryl C-H activation has been developed. This intermolecular annulation involving tandem C-H activation, cyclization and condensation steps proceeds efficiently in water, obviates the need of external oxidants, and displays a broad substituent scope.