diisobutylaluminium hydride in dichloromethane; toluene T=-78°C; Reduction; 0.75 h;

1.1: 100 percent / DIBAL-H / CH2Cl2; toluene / 0.75 h / -78 °C 2.1: aq. NH3; NH4Cl / methanol / 0.67 h / 20 °C 2.2: 84 percent / 18 h / 20 °C View Scheme