ABSTRACT Metal halide hydrates such as SnCl 2· 2H 2 O, MnCl 2· 4H 2 O, SrCl 2· 6H 2 O, CrCl 2· 6H 2 O, CoCl 2· 6H 2 O e CeCl 3· 7H 2 O were investigated as mild Lewis acids catalysts for the conjugate Friedel-Crafts reaction between indoles and activated olefins. The reactions were carried out with aliphatic unsaturated ketones over a period of days at room temperature, while chalcones reacted only under reflux conditions. The reactions with ...