1.1: O3 / CH2Cl2 / -78 °C 1.2: 87 percent / dimethylsulfide / CH2Cl2 / 2 h / 20 °C 2.1: 87 percent / DIBAL-H / CH2Cl2; hexane / -20 - 20 °C View Scheme

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