1.1: O3 / CH2Cl2 / -78 °C 1.2: Me2S / CH2Cl2 / 1.5 h / -78 - 20 °C 2.1: BuLi / tetrahydrofuran; hexane / 3 h / -45 - 20 °C 2.2: 39.6 mg / tetrahydrofuran; hexane; CH2Cl2 / 2.5 h / -45 °C View Scheme

copper(l) iodide; copper dichloride in tetrahydrofuran T=20°C; 20 h; Inert atmosphere;