methanesulfonic acid in isopropyl alcohol T=80 - 87°C; 8 h;

in isopropyl alcohol T=79 - 87°C; 4 - 10 h;

1.1: toluene / 0.25 h / 25 °C 1.2: 14 h / 10 - 75 °C / Inert atmosphere 1.3: 0.75 h / 0 - 25 °C / pH 2.5 2.1: sulfuric acid / water; methanol / 22.25 h / 25 - 65 °C 2.2: 0.75 h / 0 - 25 °C / pH 6 View Scheme

1.1: toluene / 5 h / 25 °C / Inert atmosphere 1.2: 3 h 1.3: 2 h / 40 °C 2.1: potassium carbonate / dimethyl sulfoxide / 7 h / 75 °C 3.1: water; oxalic acid / methanol / 6 h / 35 °C 3.2: 2.75 h / 10 - 30 °C / pH 7 View Scheme

1.1: toluene / 5 h / 25 °C / Inert atmosphere 1.2: 3 h 1.3: 2 h / 40 °C 2.1: potassium carbonate / dimethyl sulfoxide / 7 h / 75 °C 3.1: water; oxalic acid / methanol / 6 h / 35 °C 3.2: 2.75 h / 10 - 30 °C / pH 7 4.1: hydrogenchloride; water / methanol / 2.17 h / 25 °C 4.2: 0.92 h / 0 - 25 °C / pH 3 View Scheme

sulfuric acid in tetrahydrofuran; toluene

1: DIBAL-H / toluene / 2 h / 0 °C 2: 56.5 percent / pyridinium chlorochromate; sodium acetate / CH2Cl2 / 1 h / 20 °C View Scheme

diisobutylaluminium hydride in toluene T=0°C; 2 h;

1.1: toluene / 5 h / 25 °C / Inert atmosphere 1.2: 3 h 1.3: 2 h / 40 °C 2.1: potassium carbonate / dimethyl sulfoxide / 7 h / 75 °C View Scheme

1.1: DIBAL-H / toluene / 2 h / 0 °C 2.1: 56.5 percent / pyridinium chlorochromate; sodium acetate / CH2Cl2 / 1 h / 20 °C 3.1: n-butyllithium / tetrahydrofuran; hexane / -78 °C 3.2: tetrahydrofuran; hexane / -78 °C 4.1: 1.06 g / p-toluenesulfonic acid / tetrahydrofuran; H2O / 24 h / 20 °C 5.1: 83.5 percent / NaH; n-BuLi / tetrahydrofuran; hexane / 3 h / -10 °C View Scheme