1: (S)-α,α-diphenylprolinol - n-butylboronic acid catalyst, catecholborane / CH2Cl2 / 48 h / -20 °C 2: 89 percent / NaN3, NaOH, H2O / 1,2-dimethoxy-ethane / 24 h / 23 °C 3: 92 percent / H2 / 10percent Pd/C / ethyl acetate / 13 h / 760 Torr View Scheme