4,4′ and 5,5′-DiamBINAP as a hydrosoluble chiral ligand:: syntheses and use in Ru(II) asymmetric biphasic catalytic hydrogenation

4,4' and 5,5'-DiaminomethylBINAP were prepared in five steps from enantiomerically pure BINAP. Their synthesis involves, as key steps, the regioselective bromination of BINAP and the chemoselective efficient reduction of a dicyano, diphosphine oxide into the corresponding dicyano, diphosphine by a mixture of HSiCl3/PhSiH3. The ruthenium complexes of these new ligands were tested for the homogeneous and water/organic solvent biphasic asymmetric hydrogenation of beta-ketoesters leading to 100% conversion with an enantiomeric excess greater than 97% in water. Catalysts can be recycled several times by extraction of the product with pentane, (C) 2004 Elsevier Ltd. All rights reserved.