1: With thionyl chloride; triethylamine in dichloromethane T=0°C; 0.5 h; 2: With potassium tert-butylate in tetrahydrofuran Heating;

1.1: n-BuLi; dicyclohexylamine / tetrahydrofuran; hexane / 0.5 h / -78 °C 1.2: tetrahydrofuran; hexane / 2 h / -78 °C 2.1: thionyl chloride; triethylamine / CH2Cl2 / 0.5 h / 0 °C 2.2: potassium tert-butoxide / tetrahydrofuran / Heating View Scheme