sodium hydroxide in tetrahydrofuran; ethanol T=20°C; 2 h;

iodine cloride in acetic acid

1.1: TMEDA / diethyl ether; pentane / 0.5 h / 20 °C 2.1: n-butyllithium; TMEDA / diethyl ether; pentane / 1 h / -78 °C 2.2: I2 / diethyl ether; pentane / 1 h / -78 °C 3.1: 0.281 g / aq. HCl / methanol / -78 - 20 °C 4.1: 97 percent / aq. NaOH / ethanol; tetrahydrofuran / 2 h / 20 °C View Scheme

1: With potassium hydroxide; water 8 h; Heating / reflux; 2: With hydrogenchloride; water T=20°C; pH=2 - 3;