Synthesis of water-soluble aminosulfonamide ligands and their application in enantioselective transfer hydrogenation

Water-soluble analogues of Noyori's (1S,2S)-N-(p-tolylsulfonyl)-1,2-dipheny lethylenediamine and Knochel's (1R,2R)-N-(p-tolylsulfonyl)-1,2-diaminocyclo hexane, containing an additional sulfonic acid group, have been synthesised . The ruthenium catalysed reduction of aromatic ketones using enantiomerica lly pure catalyst derived from water soluble ligands and [RuCl2(p-cymene)]( 2) has been examined. High enantioselectivity and moderate activity were ob served in the 2-propanol/base system. The addition of water is necessary to stabilise the catalyst. (C) 2001 Elsevier Science Ltd. All rights reserved .