1: K2CO3 / ethanol / 8 h / Ambient temperature 2: pyridine / 4 h / 0 °C 3: 1) ozonised oxygen, 2) Me2S / 1) CH2Cl2, -60 deg C, 30 min, 2) up to r.t. 4: 1) BuLi, 2) HMPA / 1) hexane, THF, -78 deg C, 20 min, 2) THF a) -78 deg C, 20 min, -40 deg C, 30 min 5: 92 percent / Bu4NF / tetrahydrofuran / 4 h / Ambient temperature 6: potassium carbonate, water / methanol / Ambient temperature View Scheme