1.1: (2R,5R)-5-benzyl-2-t-Bu-3-Me-imidazolidin-4-one; TFA salt / tetrahydrofuran; H2O / 43 h / 4 °C 2.1: 65 percent / CrCl2:DMF complex / tetrahydrofuran / 3.5 h 3.1: 92 percent / H2 / Pd/C / ethyl acetate / 4.5 h 4.1: aq.NaOH / tetrahydrofuran / 5.5 h / 100 °C 4.2: 76 percent / aq. HCl / tetrahydrofuran / 3.5 h / 100 °C View Scheme