1: lead tetraacetate / CH2Cl2 / 1.) -20 deg C, 15 min, 2.) from -20 to 0 deg C, 15 min 2: hexamethylphosphoric acid triamide / 1.) -78 deg C, 30 min; 2.) from -78 deg C to 0 deg C, 90 min 3: 2.) lithium aluminum hydride / 1.) tosylation; View Scheme

1.1: Pb(OAc)4 / CH2Cl2 / 0.67 h / -20 °C 2.1: Ph3P / CH2Cl2 / 2 h / 0 °C 3.1: n-Bu3SnH; Pd(PPh3)4 / benzene / 14 h / 23 °C 4.1: 9-BBN-H / tetrahydrofuran / 3 h / 23 °C 4.2: 92 percent / Cs2CO3 / Pd(dppf)Cl2; Ph3As / tetrahydrofuran; dimethylformamide; H2O / 6 h / 23 °C 5.1: 94 percent / n-Bu4NF / tetrahydrofuran / 12 h / 23 °C 6.1: 94 percent / NaOH / tetrahydrofuran; H2O / 6 h / 23 °C View Scheme

1: Pb(OAc)4 / CH2Cl2 2: NaBH4, cyclopentene / ethanol; tetrahydrofuran / 0.5 h / -40 °C 3: 1) I2,imidazole, Ph3P, 2) aq.H2O2 / 1) benzene-acetonitrile at 23 deg C for 15 min 4: 99 percent / acetonitrile / 40 h / 60 °C 5: 1) potassium hexamethyldisilazide / 1) THF, -20 deg C, 5 min, 2) -78 deg C (30 min) to 23 deg C over 2 h 6: 1N aq.LiOH / 1,2-dimethoxy-ethane / 3 h / 23 °C View Scheme

lead(IV) acetate in dichloromethane 0.5 h; cooling;

1: lead tetraacetate / CH2Cl2 / 1.) -20 deg C, 15 min, 2.) from -20 to 0 deg C, 15 min 2: hexamethylphosphoric acid triamide / 1.) -78 deg C, 30 min; 2.) from -78 deg C to 0 deg C, 90 min 3: 1.) Jones oxidation, 0 deg C; 2.) saponification View Scheme