The effect of substituents of immobilized Rh complexes on the asymmetric hydrogenation of acetophenone derivatives

Abstract Using a modified Augustine’s method variously substituted Rh complexes were anchored on Al2O3 support. The prepared catalysts were characterized by spectroscopic methods and were applied in the hydrogenation of several acetophenone derivatives (p-CF3-acetophenone, acetophenone, p-NH2-acetophenone). Enantioselective C=O hydrogenations were observed with reasonable activity and selectivity on all heterogenized complexes, e.e. up to 80%. At the same time the immobilized samples showed the advantages of the heterogeneous systems: easy handling and recyclability.