1: 1.) aq. Na2S2O4, 2.) pyridine, DMAP / 1.) ether, 2.) CH2Cl2. RT 2: 100 percent / CF3COOH / CH2Cl2 / 12 h / 0 °C 3: 69 percent / BH3 / tetrahydrofuran / 6 h / 0 °C 4: 64 percent / pyridinium chlorochromate, Celite / CH2Cl2 / 3 h / Ambient temperature 5: 46 percent / diethyl ether; tetrahydrofuran / 2 h / -78 °C 6: 85 percent / pyridinium chlorochromate, Celite / CH2Cl2 / 3 h / Ambient temperature 7: 34 percent / ethanol; tetrahydrofuran / 2 h / -78 °C 8: 78 percent / Br2, azobisisobutylonitrile / CCl4 / 2 h / 70 °C 9: 57 percent / 1 N aq. KOH / 2 h / 0 °C View Scheme

1: 1.) aq. Na2S2O4, 2.) pyridine, DMAP / 1.) ether, 2.) CH2Cl2. RT 2: 100 percent / CF3COOH / CH2Cl2 / 12 h / 0 °C 3: 69 percent / BH3 / tetrahydrofuran / 6 h / 0 °C 4: 64 percent / pyridinium chlorochromate, Celite / CH2Cl2 / 3 h / Ambient temperature 5: 46 percent / diethyl ether; tetrahydrofuran / 2 h / -78 °C 6: 85 percent / pyridinium chlorochromate, Celite / CH2Cl2 / 3 h / Ambient temperature 7: 34 percent / ethanol; tetrahydrofuran / 2 h / -78 °C 8: 78 percent / Br2, azobisisobutylonitrile / CCl4 / 2 h / 70 °C 9: 99 percent / AgNO3 / acetone; H2O / 2 h / Ambient temperature View Scheme

<b>Multi-step reaction with 2 steps<br /> </b>1: 83 percent / 1.) TMSCl, NaBr, 2.) DMSO / acetonitrile / 2 h / Ambient temperature<br />2: 88 percent / pyridine, DMAP / CH₂Cl₂ / 4 h / Ambient temperature<br /> <br /> &nbsp;

<b>Multi-step reaction with 7 steps<br /> </b>1: 1.) lithium diisopropylamide, HMPA / 1.) hexane, THF, -78 deg C, 40 min, 2.) hexane, THF, -78 deg C, 30 min<br />2: CH₂Cl₂ / 0.5 h / -78 &deg;C<br />3: benzene / 6 h / Heating<br />4: aq. Na₂S₂O₄ / diethyl ether / 25 &deg;C<br />5: 100 percent / H₂ / 10percent Pd/C / ethyl acetate; ethanol / 8 h / Ambient temperature<br />6: 83 percent / 1.) TMSCl, NaBr, 2.) DMSO / acetonitrile / 2 h / Ambient temperature<br />7: 88 percent / pyridine, DMAP / CH₂Cl₂ / 4 h / Ambient temperature<br /> <br /> &nbsp;