1: 1.) triethylamine, ethyl chloroformate / 1.) THF, -10 deg C, 15 min, 2.)a) THF, -10 deg C, 1 h, b) RT, 3 h 2: H2, H2O / 10percent Pd/activated charcoal / methanol / 2 h / 760 Torr / Ambient temperature 3: aq. NaOH / tetrahydrofuran / 3 h / Ambient temperature View Scheme

1: H2, H2O / 10percent Pd/activated charcoal / methanol / 2 h / 760 Torr / Ambient temperature 2: aq. NaOH / tetrahydrofuran / 3 h / Ambient temperature View Scheme

1: 1.) triethylamine, ethyl chloroformate / 1.) THF, -10 deg C, 15 min, 2.)a) THF, -10 deg C, 1 h, b) RT, 3 h 2: H2, H2O / 10percent Pd/activated charcoal / methanol / 2 h / 760 Torr / Ambient temperature 3: aq. NaOH / tetrahydrofuran / 3 h / Ambient temperature View Scheme

sodium hydroxide in tetrahydrofuran 3 h; Ambient temperature; Yield given;