1: AcOH, conc. HCl / 1.5 h / Heating 2: t-BuOK / toluene / 2 h / 85 °C 3: 3M HCl / 2 h / 80 °C 4: 190 g / toluene / 3 h / 80 - 90 °C 5: Zn, KH2PO4 / tetrahydrofuran; H2O / 2 h / the temperature is kept below 30 deg C 6: NaBH4 / methanol / 1.5 h / Heating View Scheme

1: AcOH, conc. HCl / 1.5 h / Heating 2: t-BuOK / toluene / 2 h / 85 °C 3: 3M HCl / 2 h / 80 °C 4: NaBH4 / methanol / 1.5 h / Heating View Scheme