1: With oxalyl dichloride; dimethyl sulfoxide in dichloromethane T=-78 - -40°C; 1 h; 2: With triethylamine in dichloromethane T=-40 - 20°C;

1.1: borane-THF / tetrahydrofuran / 0 °C / Reflux 1.2: Cooling with ice 2.1: oxalyl dichloride; dimethyl sulfoxide / dichloromethane / 1 h / -78 - -40 °C 2.2: -40 - 20 °C View Scheme

1: With lithium hexamethyldisilazane in tetrahydrofuran T=0°C; 3 h; 2: With lithium aluminium tetrahydride in tetrahydrofuran 3 h; 3: With water; ammonium chloride; Potassium sodium tartrate in tetrahydrofuran Ice cooling;