1: 93 percent / DIBALH / toluene / 0.33 h / -78 °C 2: 83 percent / imidazole / dimethylformamide 3: 1.) O3, 2.) Ph3P / 1) CH2Cl2, MeOH, -78 deg C; 2) CH2Cl2, MeOH, rt 4: 95 percent / KOH / methanol / 20 h / 60 °C 5: 100 percent / HF / acetonitrile / 2 h 6: 72 percent / Dess-Martin periodinane / CH2Cl2 View Scheme