Synthesis of the first water-soluble chiral tetrahydroxy diphosphine Rh(I) catalyst for enantioselective hydrogenation

The synthesis of the first chiral polyhydroxy diphosphine-Rh(I) catalyst for asymmetric hydrogenation is described. Based on a simple synthetic pathway starting from D-mannitol the new metal complex is constructed. A special feature of the approach is the protection of the air-sensitive phosphine groups by the catalytically active metal in the final synthetic steps. Therefore, tedious P-protection-deprotection procedures could be advantageously avoided. The new water-soluble catalyst hydrogenates functionalized olefins by up to 99.6% ee in water as solvent. (C) 1999 Elsevier Science Ltd. All rights reserved.