1: With oxalyl dichloride; N,N-dimethyl-formamide in dichloromethane T=20°C; 1 h; 2: With sodium azide; water in acetone T=0 - 70°C;

1.1: n-butyllithium / tetrahydrofuran / 1.5 h / -65 °C / |Inert atmosphere 1.2: 0.67 h / -60 - -20 °C 2.1: oxalyl dichloride; N,N-dimethyl-formamide / dichloromethane / 1 h / 20 °C 2.2: 0 - 70 °C View Scheme