1: diisopropylamine, butyllithium / tetrahydrofuran; hexamethylphosphoric acid triamide / - 20 deg C, 20 min; r.t., overnight 2: 30percent aq. oxalic acid / tetrahydrofuran / 1.5 h / Heating 3: Zn-Hg, HCl / toluene / 10 h / Heating 4: 47percent HBr / acetic acid / 10 h / 130 °C View Scheme

1: 96 percent / aq. NaHSO3 / methanol; H2O / 24 h / Ambient temperature 2: diisopropylamine, butyllithium / tetrahydrofuran; hexamethylphosphoric acid triamide / - 20 deg C, 20 min; r.t., overnight 3: 30percent aq. oxalic acid / tetrahydrofuran / 1.5 h / Heating 4: Zn-Hg, HCl / toluene / 10 h / Heating 5: 47percent HBr / acetic acid / 10 h / 130 °C View Scheme

1: diisopropylamine, butyllithium / tetrahydrofuran; hexamethylphosphoric acid triamide / - 20 deg C, 20 min; r.t., overnight 2: 30percent aq. oxalic acid / tetrahydrofuran / 1.5 h / Heating 3: Zn-Hg, HCl / toluene / 10 h / Heating 4: 47percent HBr / acetic acid / 10 h / 130 °C View Scheme

1: Zn-Hg, HCl / toluene / 10 h / Heating 2: 47percent HBr / acetic acid / 10 h / 130 °C View Scheme

1: NaOEt / ethanol 2: aq. KOH 3: aq. KOH / acetone 4: Br2, AcOH 5: Hg(OAc)2 View Scheme

1: aq. KOH / acetone 2: Br2, AcOH 3: Hg(OAc)2 View Scheme

1: aq. KOH 2: aq. KOH / acetone 3: Br2, AcOH 4: Hg(OAc)2 View Scheme

mercury(II) diacetate

1: Br2, AcOH 2: Hg(OAc)2 View Scheme