ozone; triphenylphosphine 1.) CH2Cl2, -78 deg C, 2.) CH2Cl2; Yield givenMultistep reaction;

1: 1.) O3, 2.) PPh3 / 1.) CH2Cl2, -78 deg C, 2.) CH2Cl2 2: NaBH4 / ethanol / 0.5 h / 0 °C 3: 100 percent / I2, PPh3 / acetonitrile; diethyl ether / 1 h / 0 - 25 °C 4: 2 h / 100 °C 5: KHMDS / tetrahydrofuran / 1.) 0 deg C, 30 min, 2.) -78 deg C, 3 h 6: benzene / 18 h / Heating 7: DIBAL-H / tetrahydrofuran / 3 h / -78 °C 8: 80 percent / CCl4, PPh3 / 18 h / Heating 9: 92 percent / LiEt3BH / tetrahydrofuran / 1 h / -78 °C 10: 95 percent / CSA / methanol / 1 h / 25 °C 11: SO3*Py, DMSO, Et3N / tetrahydrofuran / 1 h / 0 °C 12: LDA / tetrahydrofuran / 1.) -78 to -40 deg C, 1 h, 2.) -78 deg C, 2 min 13: 2,6-lutidine / tetrahydrofuran / 1 h / -78 - 0 °C View Scheme

1: 1.) O3, 2.) PPh3 / 1.) CH2Cl2, -78 deg C, 2.) CH2Cl2 2: NaBH4 / ethanol / 0.5 h / 0 °C 3: 100 percent / I2, PPh3 / acetonitrile; diethyl ether / 1 h / 0 - 25 °C 4: 2 h / 100 °C 5: KHMDS / tetrahydrofuran / 1.) 0 deg C, 30 min, 2.) -78 deg C, 3 h 6: benzene / 18 h / Heating 7: DIBAL-H / tetrahydrofuran / 3 h / -78 °C 8: 80 percent / CCl4, PPh3 / 18 h / Heating 9: 92 percent / LiEt3BH / tetrahydrofuran / 1 h / -78 °C 10: 95 percent / CSA / methanol / 1 h / 25 °C 11: SO3*Py, DMSO, Et3N / tetrahydrofuran / 1 h / 0 °C 12: LDA / tetrahydrofuran / 1.) -78 to -40 deg C, 1 h, 2.) -78 deg C, 2 min View Scheme