Synthesis of a new class of chiral 1,5-diphosphanylferrocene ligands and their use in enantioselective hydrogenation

A new family of ferrocenylphosphane ligands has been prepared. Their flexible synthesis allows many structural modifications. The asymmetric induction of these ligands was examined in the hydrogenation of functionalized C=C, C=O, and C=N bonds. The enantioselectivity of the reaction was strongly dependent on the substituent R at the position alpha to the ferrocene moiety. In many cases, both enantiomeric beta-hydroxyesters of the reduction product can be obtained by simply replacing a dimethylamino group in the ligand with a methyl group.