1: 88 percent / diisobutylaluminum hydride / diethyl ether / -60 °C 2: 82 percent / xylene / 0.25 h / Heating 3: 1) O3, 2) Me2S / 1) -65 deg C, 2) r.t., 1h View Scheme

1: 88 percent / diisobutylaluminum hydride / diethyl ether / -60 °C 2: 92 percent / Swern oxidation 3: 69 percent / NaBH4 / ethanol / -60 °C 4: 92 percent / xylene / 0.25 h / Heating 5: 1) O3, 2) Me2S / 1) -65 deg C, 2) r.t. View Scheme