1: Ac2O, AcCl / acetic acid / 1.5 h / Heating 2: 84 g / aq. NaOH / ethanol / 2.5 h / Heating 3: 91 g / 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, DMAP, TEMPO / CH2Cl2 / 3.5 h / Ambient temperature 5: 72 percent / H2 / RaNi / methanol / 2.5 h 6: 99 percent / TFA / CH2Cl2 / 1 h / Ambient temperature 7: 78 percent / NaBH3CN / acetonitrile; H2O / 1 h / Ambient temperature View Scheme

1: Ac2O, AcCl / acetic acid / 1.5 h / Heating 2: 84 g / aq. NaOH / ethanol / 2.5 h / Heating View Scheme