1: With n-butyllithium in tetrahydrofuran; hexane T=-78°C; 0.5 h; Inert atmosphere; 2: With iodine in tetrahydrofuran; hexane T=-78 - 25°C; Inert atmosphere;

1.1: silica supported perchloric acid / 5 h / Inert atmosphere 2.1: n-butyllithium / tetrahydrofuran; hexane / 0.5 h / -78 °C / Inert atmosphere 2.2: -78 - 25 °C / Inert atmosphere View Scheme