1: 71 percent / O3 / CH2Cl2 / -78 °C 2: 85 percent / LiAlH4 / diethyl ether / 12 h / Heating 3: 76 percent / PBr3 / petroleum ether; pyridine / Ambient temperature View Scheme

1: 71 percent / O3 / CH2Cl2 / -78 °C 2: 85 percent / LiAlH4 / diethyl ether / 12 h / Heating View Scheme