[5]Ferrocenophane based ligands for stereoselective Rh-catalyzed hydrogenation and Cu-catalyzed Michael addition

A series of homochiral 5]ferrocenophane based N/P, N/S, N/Se, Se/P and P/P ligands was prepared from (R)-N,N-dimethylamino5]ferrocenophane. These ligands were tested in the Rh-catalyzed hydrogenation of dimethyl itaconate and in Cu-catalyzed Michael addition of Et₂Zn to cyclohex-2-enone. The best results in terms of conversion and enantioselectivity in the Rh-catalyzed hydrogenation provided bis(diphenylphosphine) ligand 2h (100% conversion and 95% ee) and aminophosphine 2a in the Cu-catalyzed conjugate addition (100% conversion 84% ee). The enantioselectivity of the Rh-catalyzed hydrogenation of methyl 2-acetamidoacrylate was lower (41% ee).