SELECTIVE HYDROGENATION OF ALPHA,BETA-UNSATURATED ALDEHYDES IN AQUEOUS ORGANIC 2-PHASE SOLVENT SYSTEMS USING RUTHENIUM OR RHODIUM COMPLEXES OF SULFONATED PHOSPHINES

Selective hydrogenation of alpha,beta-unsaturated aldehydes catalyzed by metal-sulfonated phosphine complexes prepared in situ is reported. The regioselectivity in the reduction was found to depend markedly on the nature of the metal used (Ru or Rh). Others factors controlling the activity and selectivity in the case of the ruthenium-sulfonated phosphine system were also investigated. P-31 and H-1 NMR experiments were carried out to explain the behavior of the mixture RuCl3/TPPTS (TPPTS = tris(m-sulfophenyl)phosphine trisodium salt) in water. A possible mechanism that could accommodate these results is discussed.