1: 74 percent / Et3N / benzene 2: 97 percent / TsOH / methanol / 24 h / Ambient temperature View Scheme

<b>Multi-step reaction with 24 steps<br /> </b>1: 95 percent / Et₃N / dimethylformamide<br />2: 1.) O₃, 2.) Me₂S, 3.) NaBH₄ <br />3: aq. NaIO₄ / CH₂Cl₂ / 0 &deg;C<br />4: 67 percent / NaBH(OAc)3 / benzene<br />5: 1.) BuLi, HMPA / 1.) THF, 0 deg C, 2.) THF, RT, 9 h<br />6: 1.) (COCl)2, DMSO, 2.) Et₃N<br />7: 100 percent / BuLi / tetrahydrofuran / -78 - 0 &deg;C<br />8: 75 percent / toluene / 36 h / 200 &deg;C<br />9: 80 percent / 1 N aq. HCl / tetrahydrofuran; acetone<br />10: 72 percent / NaBH₄, CeCl₃ / ethanol<br />11: 74 percent / diethyl azodicarboxylate, Ph₃P, BzONa / tetrahydrofuran<br />12: 81 percent / (MeO)3BF₄ <br />13: 79 percent / ethanol. NaOEt<br />14: 99 percent / imidazole / dimethylformamide<br />15: 75 percent / tetrahydrofuran / Ambient temperature<br />16: 89 percent / tetrabutylammonium fluoride / diethyl ether / Ambient temperature<br />17: 1.) Bu₃SnH, AIBN, 2.) SiO₂ / 1.) benzene<br />18: 90 percent / m-CPBA, NaHCO₃ <br />19: 70 percent / BF₃*Et₂O / -78 - 20 &deg;C<br />20: NH₂OH*HCl, NaOAc / ethanol<br />21: carbonyldiimidazole / CH₂Cl₂ / Ambient temperature<br />22: 1.) LiNEt₂, 2.) 2,6-di-tert-butyl-4-methylphenol / 1.) THF, 0 deg C, 30 min, 2.) THF, 30 min<br />23: 2.) H₂O / 1.) THF, -78 deg C<br />24: 96 percent / H₂ / 10percent Pd/C / ethanol<br /> <br /> &nbsp;

<b>Multi-step reaction with 21 steps<br /> </b>1: 67 percent / NaBH(OAc)3 / benzene<br />2: 1.) BuLi, HMPA / 1.) THF, 0 deg C, 2.) THF, RT, 9 h<br />3: 1.) (COCl)2, DMSO, 2.) Et₃N<br />4: 100 percent / BuLi / tetrahydrofuran / -78 - 0 &deg;C<br />5: 75 percent / toluene / 36 h / 200 &deg;C<br />6: 80 percent / 1 N aq. HCl / tetrahydrofuran; acetone<br />7: 72 percent / NaBH₄, CeCl₃ / ethanol<br />8: 74 percent / diethyl azodicarboxylate, Ph₃P, BzONa / tetrahydrofuran<br />9: 81 percent / (MeO)3BF₄ <br />10: 79 percent / ethanol. NaOEt<br />11: 99 percent / imidazole / dimethylformamide<br />12: 75 percent / tetrahydrofuran / Ambient temperature<br />13: 89 percent / tetrabutylammonium fluoride / diethyl ether / Ambient temperature<br />14: 1.) Bu₃SnH, AIBN, 2.) SiO₂ / 1.) benzene<br />15: 90 percent / m-CPBA, NaHCO₃ <br />16: 70 percent / BF₃*Et₂O / -78 - 20 &deg;C<br />17: NH₂OH*HCl, NaOAc / ethanol<br />18: carbonyldiimidazole / CH₂Cl₂ / Ambient temperature<br />19: 1.) LiNEt₂, 2.) 2,6-di-tert-butyl-4-methylphenol / 1.) THF, 0 deg C, 30 min, 2.) THF, 30 min<br />20: 2.) H₂O / 1.) THF, -78 deg C<br />21: 96 percent / H₂ / 10percent Pd/C / ethanol<br /> <br /> &nbsp;

<b>Multi-step reaction with 20 steps<br /> </b>1: 1.) BuLi, HMPA / 1.) THF, 0 deg C, 2.) THF, RT, 9 h<br />2: 1.) (COCl)2, DMSO, 2.) Et₃N<br />3: 100 percent / BuLi / tetrahydrofuran / -78 - 0 &deg;C<br />4: 75 percent / toluene / 36 h / 200 &deg;C<br />5: 80 percent / 1 N aq. HCl / tetrahydrofuran; acetone<br />6: 72 percent / NaBH₄, CeCl₃ / ethanol<br />7: 74 percent / diethyl azodicarboxylate, Ph₃P, BzONa / tetrahydrofuran<br />8: 81 percent / (MeO)3BF₄ <br />9: 79 percent / ethanol. NaOEt<br />10: 99 percent / imidazole / dimethylformamide<br />11: 75 percent / tetrahydrofuran / Ambient temperature<br />12: 89 percent / tetrabutylammonium fluoride / diethyl ether / Ambient temperature<br />13: 1.) Bu₃SnH, AIBN, 2.) SiO₂ / 1.) benzene<br />14: 90 percent / m-CPBA, NaHCO₃ <br />15: 70 percent / BF₃*Et₂O / -78 - 20 &deg;C<br />16: NH₂OH*HCl, NaOAc / ethanol<br />17: carbonyldiimidazole / CH₂Cl₂ / Ambient temperature<br />18: 1.) LiNEt₂, 2.) 2,6-di-tert-butyl-4-methylphenol / 1.) THF, 0 deg C, 30 min, 2.) THF, 30 min<br />19: 2.) H₂O / 1.) THF, -78 deg C<br />20: 96 percent / H₂ / 10percent Pd/C / ethanol<br /> <br /> &nbsp;

<b>Multi-step reaction with 18 steps<br /> </b>1: 100 percent / BuLi / tetrahydrofuran / -78 - 0 &deg;C<br />2: 75 percent / toluene / 36 h / 200 &deg;C<br />3: 80 percent / 1 N aq. HCl / tetrahydrofuran; acetone<br />4: 72 percent / NaBH₄, CeCl₃ / ethanol<br />5: 74 percent / diethyl azodicarboxylate, Ph₃P, BzONa / tetrahydrofuran<br />6: 81 percent / (MeO)3BF₄ <br />7: 79 percent / ethanol. NaOEt<br />8: 99 percent / imidazole / dimethylformamide<br />9: 75 percent / tetrahydrofuran / Ambient temperature<br />10: 89 percent / tetrabutylammonium fluoride / diethyl ether / Ambient temperature<br />11: 1.) Bu₃SnH, AIBN, 2.) SiO₂ / 1.) benzene<br />12: 90 percent / m-CPBA, NaHCO₃ <br />13: 70 percent / BF₃*Et₂O / -78 - 20 &deg;C<br />14: NH₂OH*HCl, NaOAc / ethanol<br />15: carbonyldiimidazole / CH₂Cl₂ / Ambient temperature<br />16: 1.) LiNEt₂, 2.) 2,6-di-tert-butyl-4-methylphenol / 1.) THF, 0 deg C, 30 min, 2.) THF, 30 min<br />17: 2.) H₂O / 1.) THF, -78 deg C<br />18: 96 percent / H₂ / 10percent Pd/C / ethanol<br /> <br /> &nbsp;

<b>Multi-step reaction with 23 steps<br /> </b>1: 1.) O₃, 2.) Me₂S, 3.) NaBH₄ <br />2: aq. NaIO₄ / CH₂Cl₂ / 0 &deg;C<br />3: 67 percent / NaBH(OAc)3 / benzene<br />4: 1.) BuLi, HMPA / 1.) THF, 0 deg C, 2.) THF, RT, 9 h<br />5: 1.) (COCl)2, DMSO, 2.) Et₃N<br />6: 100 percent / BuLi / tetrahydrofuran / -78 - 0 &deg;C<br />7: 75 percent / toluene / 36 h / 200 &deg;C<br />8: 80 percent / 1 N aq. HCl / tetrahydrofuran; acetone<br />9: 72 percent / NaBH₄, CeCl₃ / ethanol<br />10: 74 percent / diethyl azodicarboxylate, Ph₃P, BzONa / tetrahydrofuran<br />11: 81 percent / (MeO)3BF₄ <br />12: 79 percent / ethanol. NaOEt<br />13: 99 percent / imidazole / dimethylformamide<br />14: 75 percent / tetrahydrofuran / Ambient temperature<br />15: 89 percent / tetrabutylammonium fluoride / diethyl ether / Ambient temperature<br />16: 1.) Bu₃SnH, AIBN, 2.) SiO₂ / 1.) benzene<br />17: 90 percent / m-CPBA, NaHCO₃ <br />18: 70 percent / BF₃*Et₂O / -78 - 20 &deg;C<br />19: NH₂OH*HCl, NaOAc / ethanol<br />20: carbonyldiimidazole / CH₂Cl₂ / Ambient temperature<br />21: 1.) LiNEt₂, 2.) 2,6-di-tert-butyl-4-methylphenol / 1.) THF, 0 deg C, 30 min, 2.) THF, 30 min<br />22: 2.) H₂O / 1.) THF, -78 deg C<br />23: 96 percent / H₂ / 10percent Pd/C / ethanol<br /> <br /> &nbsp;