1.1: diphenyltetramethyldisilazane; n-butyl lithium / tetrahydrofuran / 1 h / -78 °C 1.2: NEt3 / tetrahydrofuran / 5 h / 20 °C 2.1: 57 percent / BF3*OEt2 / CH2Cl2 / 3 h / -78 °C 3.1: 90 percent / SmI2 / tetrahydrofuran / 1 h / -15 °C 4.1: 53 percent / proton sponge / CH2Cl2 / 6 h / 40 °C 5.1: 60 percent / aq. HCl / acetone / 1.33 h / 20 °C 6.1: 48 percent / NEt3 / tetrahydrofuran; CH2Cl2 / 0.5 h / 0 °C 7.1: 32 percent / titanium tetraisopropoxide / Grubbs first-generation catalyst / CH2Cl2 / 20 h / Heating 8.1: 80 percent / aq. HCl / methanol / 60 °C View Scheme

1.1: LiTMP / tetrahydrofuran / 4 h / 0 °C 1.2: tetrahydrofuran / -110 - 20 °C 2.1: 7.5 g / aq. HCl / pentane / 1 h / 20 °C 3.1: diphenyltetramethyldisilazane; n-butyl lithium / tetrahydrofuran / 1 h / -78 °C 3.2: NEt3 / tetrahydrofuran / 5 h / 20 °C 4.1: 57 percent / BF3*OEt2 / CH2Cl2 / 3 h / -78 °C 5.1: 90 percent / SmI2 / tetrahydrofuran / 1 h / -15 °C 6.1: 53 percent / proton sponge / CH2Cl2 / 6 h / 40 °C 7.1: 60 percent / aq. HCl / acetone / 1.33 h / 20 °C 8.1: 48 percent / NEt3 / tetrahydrofuran; CH2Cl2 / 0.5 h / 0 °C 9.1: 32 percent / titanium tetraisopropoxide / Grubbs first-generation catalyst / CH2Cl2 / 20 h / Heating 10.1: 80 percent / aq. HCl / methanol / 60 °C View Scheme

1: 59 percent / NaOMe / methanol; CHCl3 / 120 h / 25 °C 2: 1.) CuCl / 1.) ether, THF, -30 deg C, 20 min, 2.) -30 deg C, 20 min; 0 deg C, 40 min 3: 81 percent / NaH / dimethylformamide / 4 h / 20 °C 4: 97 percent / n-Bu4NF / tetrahydrofuran / 2.5 h / 25 °C 5: DMSO, (COCl)2 / CH2Cl2 / -78 - 0 °C 6: n-BuLi / tetrahydrofuran; hexane / 1.) -78 deg C to -40 deg C, 2.) 20 deg C, 3 h 7: 1.) B2H6*THF, 2.) 3 N NaOH, 30percent H2O2 / 1.) THF, 15-20 deg C, 30 min, 2.) EtOH, 40 deg C, 30 min 8: 100 percent / i-Pr2NEt / CH2Cl2 / 1.) 25 deg C, 5 h, 2.) 40 deg C, 2.5 h 9: 99 percent / nBu4NF / tetrahydrofuran / 2.5 h / 25 °C 10: DMSO, (COCl)2 / CH2Cl2 / 0.5 h / -78 °C 11: t-BuOK / tetrahydrofuran / 1.) 25 deg C, 1.5 h, 2.) 55 deg C, 1 h 12: methanol / 2 h / 25 °C 13: NaBH4, AcOH / 2 h / 25 °C 14: 76 percent / Na, NH3 / tetrahydrofuran / 0.25 h / -78 °C 15: 96 percent / pyridine, DMAP / 0.5 h / 0 °C 16: 42 percent / KI, ZnCu / dimethylformamide / 4 h / Heating 17: aq. acetic acid / 0.5 h / 40 °C 18: Jones reagent / acetone / 1 h / 25 °C 19: 100 percent / 80percent aq. AcOH / 3 h / Heating View Scheme

1: aq. acetic acid / 0.5 h / 40 °C 2: Jones reagent / acetone / 1 h / 25 °C 3: 100 percent / 80percent aq. AcOH / 3 h / Heating View Scheme

1: 97 percent / acetonitrile / 45 h / Heating 2: n-BuLi / tetrahydrofuran; hexane / 1.) -78 deg C to -40 deg C, 2.) 20 deg C, 3 h 3: 1.) B2H6*THF, 2.) 3 N NaOH, 30percent H2O2 / 1.) THF, 15-20 deg C, 30 min, 2.) EtOH, 40 deg C, 30 min 4: 100 percent / i-Pr2NEt / CH2Cl2 / 1.) 25 deg C, 5 h, 2.) 40 deg C, 2.5 h 5: 99 percent / nBu4NF / tetrahydrofuran / 2.5 h / 25 °C 6: DMSO, (COCl)2 / CH2Cl2 / 0.5 h / -78 °C 7: t-BuOK / tetrahydrofuran / 1.) 25 deg C, 1.5 h, 2.) 55 deg C, 1 h 8: methanol / 2 h / 25 °C 9: NaBH4, AcOH / 2 h / 25 °C 10: 76 percent / Na, NH3 / tetrahydrofuran / 0.25 h / -78 °C 11: 96 percent / pyridine, DMAP / 0.5 h / 0 °C 12: 42 percent / KI, ZnCu / dimethylformamide / 4 h / Heating 13: aq. acetic acid / 0.5 h / 40 °C 14: Jones reagent / acetone / 1 h / 25 °C 15: 100 percent / 80percent aq. AcOH / 3 h / Heating View Scheme

1: 99 percent / Et3N, DMAP / CH2Cl2 / 2.5 h / 25 °C 2: 95 percent / NaI / acetone / 15 h / Heating 3: 97 percent / acetonitrile / 45 h / Heating 4: n-BuLi / tetrahydrofuran; hexane / 1.) -78 deg C to -40 deg C, 2.) 20 deg C, 3 h 5: 1.) B2H6*THF, 2.) 3 N NaOH, 30percent H2O2 / 1.) THF, 15-20 deg C, 30 min, 2.) EtOH, 40 deg C, 30 min 6: 100 percent / i-Pr2NEt / CH2Cl2 / 1.) 25 deg C, 5 h, 2.) 40 deg C, 2.5 h 7: 99 percent / nBu4NF / tetrahydrofuran / 2.5 h / 25 °C 8: DMSO, (COCl)2 / CH2Cl2 / 0.5 h / -78 °C 9: t-BuOK / tetrahydrofuran / 1.) 25 deg C, 1.5 h, 2.) 55 deg C, 1 h 10: methanol / 2 h / 25 °C 11: NaBH4, AcOH / 2 h / 25 °C 12: 76 percent / Na, NH3 / tetrahydrofuran / 0.25 h / -78 °C 13: 96 percent / pyridine, DMAP / 0.5 h / 0 °C 14: 42 percent / KI, ZnCu / dimethylformamide / 4 h / Heating 15: aq. acetic acid / 0.5 h / 40 °C 16: Jones reagent / acetone / 1 h / 25 °C 17: 100 percent / 80percent aq. AcOH / 3 h / Heating View Scheme

1: 96 percent / pyridine, DMAP / 0.5 h / 0 °C 2: 42 percent / KI, ZnCu / dimethylformamide / 4 h / Heating 3: aq. acetic acid / 0.5 h / 40 °C 4: Jones reagent / acetone / 1 h / 25 °C 5: 100 percent / 80percent aq. AcOH / 3 h / Heating View Scheme

1: n-BuLi / tetrahydrofuran; hexane / 1.) -78 deg C to -40 deg C, 2.) 20 deg C, 3 h 2: 1.) B2H6*THF, 2.) 3 N NaOH, 30percent H2O2 / 1.) THF, 15-20 deg C, 30 min, 2.) EtOH, 40 deg C, 30 min 3: 100 percent / i-Pr2NEt / CH2Cl2 / 1.) 25 deg C, 5 h, 2.) 40 deg C, 2.5 h 4: 99 percent / nBu4NF / tetrahydrofuran / 2.5 h / 25 °C 5: DMSO, (COCl)2 / CH2Cl2 / 0.5 h / -78 °C 6: t-BuOK / tetrahydrofuran / 1.) 25 deg C, 1.5 h, 2.) 55 deg C, 1 h 7: methanol / 2 h / 25 °C 8: NaBH4, AcOH / 2 h / 25 °C 9: 76 percent / Na, NH3 / tetrahydrofuran / 0.25 h / -78 °C 10: 96 percent / pyridine, DMAP / 0.5 h / 0 °C 11: 42 percent / KI, ZnCu / dimethylformamide / 4 h / Heating 12: aq. acetic acid / 0.5 h / 40 °C 13: Jones reagent / acetone / 1 h / 25 °C 14: 100 percent / 80percent aq. AcOH / 3 h / Heating View Scheme

1: DMSO, (COCl)2 / CH2Cl2 / -78 - 0 °C 2: n-BuLi / tetrahydrofuran; hexane / 1.) -78 deg C to -40 deg C, 2.) 20 deg C, 3 h 3: 1.) B2H6*THF, 2.) 3 N NaOH, 30percent H2O2 / 1.) THF, 15-20 deg C, 30 min, 2.) EtOH, 40 deg C, 30 min 4: 100 percent / i-Pr2NEt / CH2Cl2 / 1.) 25 deg C, 5 h, 2.) 40 deg C, 2.5 h 5: 99 percent / nBu4NF / tetrahydrofuran / 2.5 h / 25 °C 6: DMSO, (COCl)2 / CH2Cl2 / 0.5 h / -78 °C 7: t-BuOK / tetrahydrofuran / 1.) 25 deg C, 1.5 h, 2.) 55 deg C, 1 h 8: methanol / 2 h / 25 °C 9: NaBH4, AcOH / 2 h / 25 °C 10: 76 percent / Na, NH3 / tetrahydrofuran / 0.25 h / -78 °C 11: 96 percent / pyridine, DMAP / 0.5 h / 0 °C 12: 42 percent / KI, ZnCu / dimethylformamide / 4 h / Heating 13: aq. acetic acid / 0.5 h / 40 °C 14: Jones reagent / acetone / 1 h / 25 °C 15: 100 percent / 80percent aq. AcOH / 3 h / Heating View Scheme

1: 81 percent / NaH / dimethylformamide / 4 h / 20 °C 2: 97 percent / n-Bu4NF / tetrahydrofuran / 2.5 h / 25 °C 3: DMSO, (COCl)2 / CH2Cl2 / -78 - 0 °C 4: n-BuLi / tetrahydrofuran; hexane / 1.) -78 deg C to -40 deg C, 2.) 20 deg C, 3 h 5: 1.) B2H6*THF, 2.) 3 N NaOH, 30percent H2O2 / 1.) THF, 15-20 deg C, 30 min, 2.) EtOH, 40 deg C, 30 min 6: 100 percent / i-Pr2NEt / CH2Cl2 / 1.) 25 deg C, 5 h, 2.) 40 deg C, 2.5 h 7: 99 percent / nBu4NF / tetrahydrofuran / 2.5 h / 25 °C 8: DMSO, (COCl)2 / CH2Cl2 / 0.5 h / -78 °C 9: t-BuOK / tetrahydrofuran / 1.) 25 deg C, 1.5 h, 2.) 55 deg C, 1 h 10: methanol / 2 h / 25 °C 11: NaBH4, AcOH / 2 h / 25 °C 12: 76 percent / Na, NH3 / tetrahydrofuran / 0.25 h / -78 °C 13: 96 percent / pyridine, DMAP / 0.5 h / 0 °C 14: 42 percent / KI, ZnCu / dimethylformamide / 4 h / Heating 15: aq. acetic acid / 0.5 h / 40 °C 16: Jones reagent / acetone / 1 h / 25 °C 17: 100 percent / 80percent aq. AcOH / 3 h / Heating View Scheme