Transfer hydrogenylysis of trichloromethyl compounds by alcohols and polystyrene-anchored Rh, Ru and Ir complexes

Polystyrene-anchored RhCl[P(C₆H₅)₃]₃, RuCl₂[P(C₆H₅)₃]₃ and IrCl-(CO)[P(C₆H₅)₃]₂ were shown to catalyze selective transfer hydrogenolysis of various trichloromethyl compounds between 140 and 160 °C in the presence of 2-propanol. 2,2,2-Trichloro-1-phenylethanol, 2,2,2-trichloro-acetophenone and 2-propyl trichloroacetate were converted into 2,2-dichloro-1-phenylethanol, 2,2-dichloroacetophenone and 2-propyl dichloro-acetate, respectively. 1,3,3,3-Tetrachloropropylbenzene gave a 1:1 mixture of 1,3,3- and 3,3,3-trichloropropylbenzene. Under the reaction conditions the catalysts proved to be resistant to leaching. Owing to saturation of the active sites with HCl, the catalytic power dropped after several runs, but it could be restored by extrusion of part of the metal-coordinated chlorine with the aid of air or oxygen.