1.1: NaH / tetrahydrofuran / 0.17 h / 0 °C 1.2: tetrahydrofuran / 8 h / 0 °C 2.1: p-toluenesufonic acid monohydrate / toluene / 20 h / 80 °C View Scheme

1: NaH / tetrahydrofuran / 1.) 0 deg C, 10 min, 2.) 0 deg C, 5 h 2: TsOH / benzene / 16 h / Heating 3: aq. LiOH / tetrahydrofuran / 1 h / Ambient temperature View Scheme