Catalytic Hydrogenation with Rhodium Complexes Containing dipamp‐pyrphos Hybrid Ligands

Very high enantiomeric excesses are more easily achieved when the catalyst contains a C 2 ‐symmetric ligand as a chiral inductor—this, however, does not hold for hydrogenation, catalyzed by rhodium complexes with 3,4‐bis(phosphino)pyrrolidine ligands (e.g., 1 ). In the hydrogenation of ( Z )‐α‐acetoamidocinnamic acid the results obtained with the asymmetric ligand are similar to those with the C 2 ‐symmetric ligands. Boc = tert ‐butoxycarbonyl.