1.1: ethanol / 1 h 2.1: potassium carbonate / water / 0.5 h / 25 - 30 °C 2.2: 12 h / 25 - 75 °C 3.1: hydrogen bromide / water; acetone / 7 h / 0 - 20 °C View Scheme

1.1: toluene-4-sulfonic acid / methanol / 0.5 h / 0 - 5 °C 1.2: 6 h / 0 - 5 °C 2.1: sodium tetrahydroborate / tetrahydrofuran / 1 h / 5 - 10 °C / |Inert atmosphere 2.2: 4 h / 45 - 50 °C / |Inert atmosphere 3.1: potassium carbonate / water / 0.5 h / 25 - 30 °C 3.2: 12 h / 25 - 75 °C 4.1: hydrogen bromide / water; acetone / 7 h / 0 - 20 °C View Scheme

1.1: sodium tetrahydroborate / tetrahydrofuran / 1 h / 5 - 10 °C / |Inert atmosphere 1.2: 4 h / 45 - 50 °C / |Inert atmosphere 2.1: potassium carbonate / water / 0.5 h / 25 - 30 °C 2.2: 12 h / 25 - 75 °C 3.1: hydrogen bromide / water; acetone / 7 h / 0 - 20 °C View Scheme

1.1: AlCl3, aluminium chloride / dichloromethane / 0.5 h / 0 - 5 °C / |Inert atmosphere 1.2: 0.5 h / 0 - 5 °C / |Inert atmosphere 2.1: toluene-4-sulfonic acid / methanol / 0.5 h / 0 - 5 °C 2.2: 6 h / 0 - 5 °C 3.1: sodium tetrahydroborate / tetrahydrofuran / 1 h / 5 - 10 °C / |Inert atmosphere 3.2: 4 h / 45 - 50 °C / |Inert atmosphere 4.1: potassium carbonate / water / 0.5 h / 25 - 30 °C 4.2: 12 h / 25 - 75 °C 5.1: hydrogen bromide / water; acetone / 7 h / 0 - 20 °C View Scheme

sodium hydroxide in water T=20 - 25°C; pH=12;