1: Et3N / CH2Cl2 / 1 h / 3 °C 2: TiCl4 / CH2Cl2 / 3 h / -78 - -15 °C 3: aq. HF / acetonitrile / 2 h / Ambient temperature 4: 72 percent / O2, CuCl, H2O / PdCl2 / dimethylformamide / 15 h / 25 °C 5: 41 percent / TESOTf, 2,6-lutidine / CH2Cl2 / 4 h / 25 °C 6: 64 percent / 2,6-lutidine / CH2Cl2 / 1 h / -35 °C 7: 77 percent / aq. HF / acetonitrile / 1 h / 3 °C View Scheme

<b>Multi-step reaction with 18 steps<br /> </b>1: 1.) (COCl)2, DMSO, 2.) Et₃N / 1.) CH₂Cl₂, -78 deg C, 30 min, 2.) 25 deg C, 30 min<br />2: BF₃*Et₂O / CH₂Cl₂ / 1.) -86 deg C, 15 min; -86 to -70 deg C, 45 min, 2.) 0 deg C, 1 h<br />3: 100 percent / i-Pr₂NEt / CH₂Cl₂ / 18 h / 25 &deg;C<br />4: 1.) 9-BBN, 2.) 3 N aq. NaOH, 31percent aq. H₂O₂ / 1.) THF, 25 deg C, 17 h, 2.) 25 deg C, 7 h<br />5: 87 percent / pyridine, n-Bu₃P / 45 h / 25 &deg;C<br />6: 100 percent / 80percent m-CPBA, NaHCO₃ / CH₂Cl₂ / 1.5 h / 25 &deg;C<br />7: n-BuLi / diethyl ether; hexane / 1.) -78 deg C, 30 min, 2.) 25 deg C, 4.5 h<br />8: 1.) (COCl)2, DMSO, 2.) Et₃N / 1.) CH₂Cl₂, -78 deg C, 30 min, 2.) 5 deg C, 30 min<br />9: 51 percent / SmI₂ / tetrahydrofuran; methanol / 0.33 h / -78 &deg;C<br />10: 91 percent / K₂CO₃ / methanol / 2.5 h / 60 &deg;C<br />11: 79 percent / TMSBr / CH₂Cl₂ / 1.) -30 deg C, 5 min, 2.) 3 deg C, 30 min<br />12: 100 percent / TBAF / tetrahydrofuran / 5.5 h / 25 &deg;C<br />13: 80 percent / Dess-Martin periodinane / CH₂Cl₂ / 2 h / 25 &deg;C<br />14: 86 percent / molecular sieves 4 Angstroem / toluene / 1.) -78 deg C, 2 h, 2.) -78 deg C to r.t.<br />15: 85 percent / t-BuOOH / VO(acac)2 / CH₂Cl₂ / 7 h / 25 &deg;C<br />16: 92 percent / Et₃N, DMAP / CH₂Cl₂ / 2.5 h / 3 &deg;C<br />17: 90 percent / LiEt₃BH / tetrahydrofuran / 1 h / 3 &deg;C<br />18: 95 percent / PDC, molecular sieves 3 Angstroem / CH₂Cl₂ / 1 h / 25 &deg;C<br /> <br /> &nbsp;

<b>Multi-step reaction with 10 steps<br /> </b>1: 87 percent / 2,6-lutidine / CH₂Cl₂ / 1.5 h / -45 - 3 &deg;C<br />2: 43 percent / LiHMDS / tetrahydrofuran / 1.) -78 deg C, 1 h, 2.) -78 deg C, 30 min; 0 deg C, 2 h<br />3: 100 percent / LiCl, n-Bu₃SnH, Pd(PPh₃)4 / tetrahydrofuran / 3 h / Heating<br />4: 99 percent / aq. HF / acetonitrile / 2 h / 15 &deg;C<br />5: 84 percent / toluene / 3 h / 170 &deg;C<br />6: 86 percent / molecular sieves 4 Angstroem / toluene / 1.) -78 deg C, 2 h, 2.) -78 deg C to r.t.<br />7: 85 percent / t-BuOOH / VO(acac)2 / CH₂Cl₂ / 7 h / 25 &deg;C<br />8: 92 percent / Et₃N, DMAP / CH₂Cl₂ / 2.5 h / 3 &deg;C<br />9: 90 percent / LiEt₃BH / tetrahydrofuran / 1 h / 3 &deg;C<br />10: 95 percent / PDC, molecular sieves 3 Angstroem / CH₂Cl₂ / 1 h / 25 &deg;C<br /> <br /> &nbsp;

<b>Multi-step reaction with 16 steps<br /> </b>1: 87 percent / Zn / aq. ethanol / 22 h / Heating<br />2: 67 percent / PPh₃, DEAD / benzene / 15 h / 25 &deg;C<br />3: 80 percent / NaH / methanol / 2 h / 5 &deg;C<br />4: 1.) (COCl)2, DMSO, 2.) Et₃N / 1.) CH₂Cl₂, -78 deg C, 30 min, 2.) 0 deg C, 10 min<br />5: n-BuLi / diethyl ether; hexane / 1.) -78 deg C, 30 min, 2.) 25 deg C, 4.5 h<br />6: 1.) (COCl)2, DMSO, 2.) Et₃N / 1.) CH₂Cl₂, -78 deg C, 30 min, 2.) 5 deg C, 30 min<br />7: 51 percent / SmI₂ / tetrahydrofuran; methanol / 0.33 h / -78 &deg;C<br />8: 91 percent / K₂CO₃ / methanol / 2.5 h / 60 &deg;C<br />9: 79 percent / TMSBr / CH₂Cl₂ / 1.) -30 deg C, 5 min, 2.) 3 deg C, 30 min<br />10: 100 percent / TBAF / tetrahydrofuran / 5.5 h / 25 &deg;C<br />11: 80 percent / Dess-Martin periodinane / CH₂Cl₂ / 2 h / 25 &deg;C<br />12: 86 percent / molecular sieves 4 Angstroem / toluene / 1.) -78 deg C, 2 h, 2.) -78 deg C to r.t.<br />13: 85 percent / t-BuOOH / VO(acac)2 / CH₂Cl₂ / 7 h / 25 &deg;C<br />14: 92 percent / Et₃N, DMAP / CH₂Cl₂ / 2.5 h / 3 &deg;C<br />15: 90 percent / LiEt₃BH / tetrahydrofuran / 1 h / 3 &deg;C<br />16: 95 percent / PDC, molecular sieves 3 Angstroem / CH₂Cl₂ / 1 h / 25 &deg;C<br /> <br /> &nbsp;

<b>Multi-step reaction with 21 steps<br /> </b>1: LiAlH₄ / diethyl ether / 0.5 h / 25 &deg;C<br />2: 99 percent / imidazole / dimethylformamide / 18 h / 25 &deg;C<br />3: 80 percent / p-TsOH*H₂O / methanol / 0.83 h / 25 &deg;C<br />4: 1.) (COCl)2, DMSO, 2.) Et₃N / 1.) CH₂Cl₂, -78 deg C, 30 min, 2.) 25 deg C, 30 min<br />5: BF₃*Et₂O / CH₂Cl₂ / 1.) -86 deg C, 15 min; -86 to -70 deg C, 45 min, 2.) 0 deg C, 1 h<br />6: 100 percent / i-Pr₂NEt / CH₂Cl₂ / 18 h / 25 &deg;C<br />7: 1.) 9-BBN, 2.) 3 N aq. NaOH, 31percent aq. H₂O₂ / 1.) THF, 25 deg C, 17 h, 2.) 25 deg C, 7 h<br />8: 87 percent / pyridine, n-Bu₃P / 45 h / 25 &deg;C<br />9: 100 percent / 80percent m-CPBA, NaHCO₃ / CH₂Cl₂ / 1.5 h / 25 &deg;C<br />10: n-BuLi / diethyl ether; hexane / 1.) -78 deg C, 30 min, 2.) 25 deg C, 4.5 h<br />11: 1.) (COCl)2, DMSO, 2.) Et₃N / 1.) CH₂Cl₂, -78 deg C, 30 min, 2.) 5 deg C, 30 min<br />12: 51 percent / SmI₂ / tetrahydrofuran; methanol / 0.33 h / -78 &deg;C<br />13: 91 percent / K₂CO₃ / methanol / 2.5 h / 60 &deg;C<br />14: 79 percent / TMSBr / CH₂Cl₂ / 1.) -30 deg C, 5 min, 2.) 3 deg C, 30 min<br />15: 100 percent / TBAF / tetrahydrofuran / 5.5 h / 25 &deg;C<br />16: 80 percent / Dess-Martin periodinane / CH₂Cl₂ / 2 h / 25 &deg;C<br />17: 86 percent / molecular sieves 4 Angstroem / toluene / 1.) -78 deg C, 2 h, 2.) -78 deg C to r.t.<br />18: 85 percent / t-BuOOH / VO(acac)2 / CH₂Cl₂ / 7 h / 25 &deg;C<br />19: 92 percent / Et₃N, DMAP / CH₂Cl₂ / 2.5 h / 3 &deg;C<br />20: 90 percent / LiEt₃BH / tetrahydrofuran / 1 h / 3 &deg;C<br />21: 95 percent / PDC, molecular sieves 3 Angstroem / CH₂Cl₂ / 1 h / 25 &deg;C<br /> <br /> &nbsp;