1.1: water; sodium hydroxide / methanol / 4 h 2.1: toluene-4-sulfonic acid / dichloromethane / 15 h / 20 °C / Inert atmosphere 3.1: n-butyllithium / tetrahydrofuran / 0.17 h / -98 °C / Inert atmosphere 3.2: 1.67 h / -98 - 20 °C / Inert atmosphere 4.1: water / tetrahydrofuran / 1 h / 20 °C 5.1: magnesium sulfate / dichloromethane / 15 h / 20 °C / Inert atmosphere 6.1: N,N,N',N,-tetramethylethylenediamine; sec.-butyllithium / diethyl ether / -78 °C / Inert atmosphere 6.2: -98 - -78 °C / Inert atmosphere 7.1: toluene-4-sulfonic acid / diethyl ether / Inert atmosphere; Reflux 8.1: water; sodium tris(acetoxy)borohydride; acetic acid / dichloromethane / 16 h / 20 °C View Scheme

1.1: water; sodium hydroxide / methanol / 4 h 2.1: toluene-4-sulfonic acid / dichloromethane / 15 h / 20 °C / Inert atmosphere 3.1: n-butyllithium / tetrahydrofuran / 0.17 h / -98 °C / Inert atmosphere 3.2: 1.67 h / -98 - 20 °C / Inert atmosphere 4.1: water / tetrahydrofuran / 1 h / 20 °C 5.1: magnesium sulfate / dichloromethane / 15 h / 20 °C / Inert atmosphere 6.1: N,N,N',N,-tetramethylethylenediamine; sec.-butyllithium / diethyl ether / -78 °C / Inert atmosphere 6.2: -98 - -78 °C / Inert atmosphere 7.1: toluene-4-sulfonic acid / diethyl ether / Inert atmosphere; Reflux View Scheme

sodium hydroxide in methanol T=20°C; 1 h;