1.1: 94 percent / NaBH4 / tetrahydrofuran / 0.5 h / -20 °C 2.1: POCl3 3.1: dimethylformamide / 20 °C 4.1: TsOH / methanol / 12 h / 20 °C 5.1: 65 percent / n-BuLi 6.1: 100 percent / LiBHEt3; Pd(dppp)Cl2 / tetrahydrofuran / 3 h / 0 °C 7.1: N-chlorosuccinimide; Me2S / CH2Cl2 / 2.5 h / 0 °C 8.1: n-BuLi 8.2: -78 - 20 °C 9.1: LiBHEt3; Pd(dppp)Cl2 / tetrahydrofuran 10.1: TBAF / tetrahydrofuran / 1 h 11.1: Cp2ZrCl2 / 1,2-dichloro-ethane; hexane 11.2: 83 percent / NiCl2(PPh3)2; n-BuLi / tetrahydrofuran; hexane View Scheme

1: 54 percent / p-toluenesulfonic acid / cyclohexane / Heating 2: 1.) NaOCH3 / 1.) CH3OH, RT, 0.5 h, 2.) CH3OH, RT, overnight 3: aq. NaOH / 2 h / 60 °C 4: 1.) Mg / 1.) THF, 2.) THF, 30 deg C, 0.5 h 5: 79 percent / aq. oxalic acid / acetone / 1 h / Ambient temperature 6: KHSO4 / 180 °C View Scheme

1: 54 percent / p-toluenesulfonic acid / cyclohexane / Heating 2: 1.) NaOCH3 / 1.) CH3OH, RT, 0.5 h, 2.) CH3OH, RT, overnight 3: aq. NaOH / 2 h / 60 °C 4: 1.) Mg / 1.) THF, 2.) THF, 30 deg C, 0.5 h 5: 79 percent / aq. oxalic acid / acetone / 1 h / Ambient temperature View Scheme

1.1: 94 percent / NaBH4 / tetrahydrofuran / 0.5 h / -20 °C 2.1: POCl3 3.1: dimethylformamide / 20 °C 4.1: TsOH / methanol / 12 h / 20 °C 5.1: 65 percent / n-BuLi 6.1: 100 percent / LiBHEt3; Pd(dppp)Cl2 / tetrahydrofuran / 3 h / 0 °C 7.1: N-chlorosuccinimide; Me2S / CH2Cl2 / 2.5 h / 0 °C 8.1: 79 percent / n-BuLi 9.1: LiBHEt3; Pd(dppp)Cl2 / tetrahydrofuran 10.1: TBAF / tetrahydrofuran 11.1: Cp2ZrCl2 / 1,2-dichloro-ethane; hexane 11.2: 89 percent / NiCl2(PPh3)2; n-BuLi / tetrahydrofuran; hexane View Scheme

1.1: 80 percent / NaBH4 / tetrahydrofuran / 5 h / -20 °C 2.1: tris(tetra-n-butylammonium) hydrogen pyrophosphate / acetonitrile / 2 h / 20 °C 2.2: 83 percent / Dowex 50WX8-200; NH4HCO3 / propan-2-ol / pH 8.0 View Scheme