1: 92 percent / PBr3 / petroleum ether / 1 h / 0 °C 2: 1) NaI, 2) NaBH4 / 1) DMSO, r.t., 15 min, 2) MeOH, 1.5 h 3: 90 percent / DIBAL-H / benzene; toluene / 2 h / 0 °C View Scheme

1: 75 percent / p-toluenesulphonic acid / toluene / 30 h / Heating 2: 63 percent / DIBAL-H / benzene / 2.5 h / Ambient temperature 3: tetrahydrofuran / 0.17 h / 0 °C 4: 100 percent / MnO2 / petroleum ether / 1 h View Scheme

1.1: 66 percent / pyridinium chlorochromate / CH2Cl2 / 0 - 20 °C 2.1: p-toluenesulfonic acid; trimethyl orthoformate 2.2: 89 percent / HCl / acetone 3.1: 72 percent / DIBAL-H / petroleum ether / 1 h / -60 - 20 °C 4.1: nBuLi / tetrahydrofuran / -20 °C 4.2: 79 percent / tetrahydrofuran / 1 h / 0 - 20 °C 5.1: 52 percent / DIBAL-H / petroleum ether / -80 - -20 °C 6.1: 97 percent / HCl / acetone; H2O 7.1: LDA / tetrahydrofuran / 0.17 h / -20 °C 7.2: 69 percent / (+)-(8,8-dichlorocamphorsulfonyl)oxaziridine / tetrahydrofuran / 1.25 h / -20 - 20 °C 8.1: HBr / CH2Cl2 / 0 °C 9.1: 1,2-epoxybutane / ethyl acetate / 24 h / 20 °C 10.1: 55 percent / various solvent(s) / 20 h / 63 °C View Scheme

1: 92 percent / PBr3 / petroleum ether / 1 h / 0 °C 2: 1) NaI, 2) NaBH4 / 1) DMSO, r.t., 15 min, 2) MeOH, 1.5 h View Scheme

1.1: 77 percent / p-TsOH / toluene / Heating 2.1: Dibal-H / petroleum ether; hexane / 0.5 h / -60 - 20 °C 2.2: 92 percent / SiO2 / H2O; toluene / 1 h / -20 - 0 °C View Scheme

toluene-4-sulfonic acid in toluene Heating;

1: 92 percent / PBr3 / petroleum ether / 1 h / 0 °C 2: 1) NaI, 2) NaBH4 / 1) DMSO, r.t., 15 min, 2) MeOH, 1.5 h View Scheme