1: O3, pyridine / 1.) CH2Cl2, -78 deg C, 2.) CH2Cl2, RT, 2 h 2: 98 percent / NaBH4 / methanol / 0.5 h 3: 92 percent / Ph3P, imidazole, I2 / diethyl ether; acetonitrile / 0.75 h 4: 68 percent / 3 h / 180 - 200 °C 5: 1.) BuLi, 4A molecular sieve, SiO2 / 1.) DME, hexane, -78 deg C, 30 min, 2.) DME, hexane, a) -78 deg C, 30 min, b) reflux, overnight 6: 96 percent / TsOH / acetone / 4 h / 50 °C 7: 81 percent / TiCl4, Zn / 1,2-dimethoxy-ethane / 3 h / Ambient temperature View Scheme