pyridine in dichloromethane T=-78 - 20°C;

1.1: carbonyl diimidazole / CH2Cl2 / 0.75 h 1.2: CH2Cl2 2.1: n-BuLi / tetrahydrofuran; hexane / 0.17 h / -78 °C 2.2: tetrahydrofuran; hexane / -78 - 20 °C 3.1: BCl3 / CH2Cl2 / -78 - 20 °C 4.1: pyridine / CH2Cl2 / -78 - 20 °C View Scheme

1.1: n-BuLi / tetrahydrofuran; hexane / 0.17 h / -78 °C 1.2: tetrahydrofuran; hexane / -78 - 20 °C 2.1: BCl3 / CH2Cl2 / -78 - 20 °C 3.1: pyridine / CH2Cl2 / -78 - 20 °C View Scheme

1,8-diazabicyclo[5.4.0]undec-7-ene in N,N-dimethyl-formamide T=90°C; 3 h;

1,8-diazabicyclo[5.4.0]undec-7-ene in N,N-dimethyl-formamide T=90°C; 18 h;