Synthesis of new chiral diphosphine ligand (BisbenzodioxanPhos) and its application in asymmetric catalytic hydrogenation

The new chiral diphosphine ligand [(5.6) (5'.6')-bis(1.2-ethylenedioxy)biphenyl-2.2'-diyl]bis(diphenylphosphine) (Bisben-zodioxanPhos) has been successfully prepared and used in ruthenium-catalyzed asymmetric hydrogenation of 2-(6'-methoxy-2'-naphthyl)propenoic acid and beta-keto esters with high enantioselectivity (92.2% and up to 99.5% ee. respectively). (C) 2002 Published by Elsevier Science Ltd.