1: 1) lithium hexamethyldisilazide / 1) THF, -78 deg C, 1h, 2) room temperature, 30 min 2: tetrahydrofuran / -78 °C 3: DIBAL-H / toluene / 2 h / -78 °C 4: 96 percent / pyridine, DMAP / CH2Cl2 / 2 h / 0 °C 5: 1) hexamethyldisilazane (HMDS), ammonium sulfate, 2) trimethylsilyl triflate (TMSOTf) / 1) reflux, 1 h, 2) 1,2-dichloroethane, a) -22 deg C, 15 min, b) room temperature, 0.5 h 6: 59 percent / ammonia / methanol / 16 h / 80 °C 7: 90.9 percent / n-Bu3SnH, Et3B / benzene; hexane / Ambient temperature 8: 82.4 percent / TBAF / tetrahydrofuran / Ambient temperature View Scheme

1: 1) lithium hexamethyldisilazide / 1) THF, -78 deg C, 1h, 2) room temperature, 30 min 2: tetrahydrofuran / -78 °C 3: DIBAL-H / toluene / 2 h / -78 °C 4: 96 percent / pyridine, DMAP / CH2Cl2 / 2 h / 0 °C 5: 1) hexamethyldisilazane (HMDS), ammonium sulfate, 2) trimethylsilyl triflate (TMSOTf) / 1) reflux, 3 h, 2) 1,2-dichlorethane, a) 5 deg C, 10 min, b) room temperature, 35 min 6: 94.74 percent / n-Bu3SnH, Et3B / benzene; hexane / Ambient temperature 7: 99.5 percent / TBAF / tetrahydrofuran / Ambient temperature 8: 88.73 percent / sodium methoxide / methanol / 1 h / Ambient temperature View Scheme

1: 1) lithium hexamethyldisilazide / 1) THF, -78 deg C, 1h, 2) room temperature, 30 min 2: tetrahydrofuran / -78 °C 3: DIBAL-H / toluene / 2 h / -78 °C 4: 96 percent / pyridine, DMAP / CH2Cl2 / 2 h / 0 °C 5: 1) hexamethyldisilazane (HMDS), ammonium sulfate, 2) trimethylsilyl triflate (TMSOTf) / 1) reflux, 2 h, 2) 1,2-dichloroethane, a) 5 deg C, 10 min, b) room temperature, 10 min 6: 76 percent / 30percent aq. H2O2, pyridine / CH2Cl2 / 0.5 h / Ambient temperature 7: 78 percent / TBAF / tetrahydrofuran / Ambient temperature View Scheme

1.1: 95 percent / DIBAL / CH2Cl2 / 2 h / -78 °C 2.1: 77 percent / mesyl chloride; triethylamine / CH2Cl2 / 2.5 h / -20 - 40 °C 3.1: t-BuLi / tetrahydrofuran / 0.75 h / -78 - 0 °C 3.2: 85 percent / TMEDA / tetrahydrofuran / 12 h / 20 °C 4.1: ThxBH2 / tetrahydrofuran / 16 h / 0 °C 4.2: 59 percent / aq. NaOH; aq. H2O2 / 6 h / 20 °C 5.1: 93 percent / TBAF / tetrahydrofuran / 2 h / 0 - 20 °C 6.1: 74 percent / triphenylphosphine; iodine; imidazole / toluene / 3 h / 70 °C 7.1: 92 percent / ethanol / 3 h / Heating View Scheme

1: 1) lithium hexamethyldisilazide / 1) THF, -78 deg C, 1h, 2) room temperature, 30 min 2: tetrahydrofuran / -78 °C 3: DIBAL-H / toluene / 2 h / -78 °C 4: 96 percent / pyridine, DMAP / CH2Cl2 / 2 h / 0 °C 5: 1) hexamethyldisilazane (HMDS), ammonium sulfate, 2) trimethylsilyl triflate (TMSOTf) / 1) reflux, 1 h, 2) 1,2-dichloroethane, a) -22 deg C, 15 min, b) room temperature, 0.5 h 6: 90 percent / mercaptoethanol, sodium methoxide / methanol / 4 h / Heating 7: 90 percent / n-Bu3SnH, Et3B / benzene; hexane / Ambient temperature 8: 79 percent / TBAF / tetrahydrofuran / Ambient temperature View Scheme

1: 92 percent / DIBAL / 0.08 h / -78 °C 2: CCl4, tris(dimethylamino)phosphane / tetrahydrofuran / 4 h / -80 °C 3: 20 percent / KOH, tris<2-(2-methoxyethoxy)ethyl>amine / acetonitrile / 0.5 h / Ambient temperature 4: 82 percent / Bu4NF / tetrahydrofuran / 0.5 h / Ambient temperature View Scheme

1: 1) lithium hexamethyldisilazide / 1) THF, -78 deg C, 1h, 2) room temperature, 30 min 2: tetrahydrofuran / -78 °C 3: DIBAL-H / toluene / 2 h / -78 °C 4: 96 percent / pyridine, DMAP / CH2Cl2 / 2 h / 0 °C 5: 1) hexamethyldisilazane (HMDS), ammonium sulfate, 2) trimethylsilyl triflate (TMSOTf) / 1) reflux, 2 h, 2) 1,2-dichlorethane, a) 5 deg C, 10 min, b) room temperature, 10 min 6: 81.1 percent / n-Bu3SnH, Et3B / benzene; hexane / Ambient temperature 7: 84.8 percent / TBAF / tetrahydrofuran / 3 h / Ambient temperature View Scheme

1: 1) lithium hexamethyldisilazide / 1) THF, -78 deg C, 1h, 2) room temperature, 30 min 2: tetrahydrofuran / -78 °C 3: DIBAL-H / toluene / 2 h / -78 °C 4: 96 percent / pyridine, DMAP / CH2Cl2 / 2 h / 0 °C 5: 1) hexamethyldisilazane (HMDS), ammonium sulfate, 2) trimethylsilyl triflate (TMSOTf) / 1) reflux, 2 h, 2) 1,2-dichloroethane, a) 5 deg C, 10 min, b) room temperature, 10 min 6: 89 percent / n-Bu3SnH, Et3B / benzene; hexane / 4 h / Ambient temperature 7: 80 percent / TBAF / tetrahydrofuran / 3 h / Ambient temperature View Scheme

1: 1) lithium hexamethyldisilazide / 1) THF, -78 deg C, 1h, 2) room temperature, 30 min 2: tetrahydrofuran / -78 °C 3: DIBAL-H / toluene / 2 h / -78 °C 4: 96 percent / pyridine, DMAP / CH2Cl2 / 2 h / 0 °C 5: 1) hexamethyldisilazane (HMDS), ammonium sulfate, 2) trimethylsilyl triflate (TMSOTf) / 1) reflux, 1 h, 2) 1,2-dichloroethane, a) -22 deg C, 15 min, b) room temperature, 0.5 h 6: 85.5 percent / methanol; H2O / 18 h / 85 °C 7: 96.5 percent / 30percent aq. H2O2, pyridine / CH2Cl2 / Ambient temperature 8: 90 percent / TBAF / tetrahydrofuran / Ambient temperature View Scheme

1: 1) lithium hexamethyldisilazide / 1) THF, -78 deg C, 1h, 2) room temperature, 30 min 2: tetrahydrofuran / -78 °C 3: DIBAL-H / toluene / 2 h / -78 °C 4: 96 percent / pyridine, DMAP / CH2Cl2 / 2 h / 0 °C 5: 1) hexamethyldisilazane (HMDS), ammonium sulfate, 2) trimethylsilyl triflate (TMSOTf) / 1) reflux, 1 h, 2) 1,2-dichloroethane, a) -22 deg C, 15 min, b) room temperature, 0.5 h 6: 93 percent / n-Bu3SnH, Et3B / benzene; hexane / Ambient temperature 7: 83 percent / TBAF / tetrahydrofuran / Ambient temperature View Scheme