iridium-catalyzed asymmetrichydrogenation of prochiralolefins. Our results show that the enantiomeric excesses are strongly dependent on the absolute configuration of the C-3 stereocenter of the carbohydrate backbone and on the metal source. Enantiomeric excesses of up to 78% with moderate to high activities were obtained under very mild reactions conditions with the catalytic systems [Rh(cod)(2)]BF4