diisobutylaluminium hydride in toluene T=-78°C; 2 h;

1.1: lithium aluminum hydride / tetrahydrofuran / 1.5 h / 0 - 20 °C 2.1: Et3N / CH2Cl2 / 0.33 h / -50 - -20 °C 3.1: 0.66 g / NaN3 / dimethylsulfoxide / 16 h 4.1: mercuric perchlorate trihydrate / tetrahydrofuran / 0.75 h / 20 °C 4.2: 58 percent / sodium borohydride; sodium hydroxide / H2O; tetrahydrofuran / 2 h View Scheme