1.1: pyridinium p-toluenesulfonate / CH2Cl2 / 12 h / 20 °C 2.1: tetrabutylammonium fluoride / tetrahydrofuran / 16 h / 0 °C 3.1: PCC; 4 Angstroem molecular sieves / CH2Cl2 / 1 h / 0 °C 4.1: NaH / tetrahydrofuran / 0.08 h / 20 °C 4.2: tetrahydrofuran / 1 h 5.1: LiAlH4; (S)-binaphthol / tetrahydrofuran; ethanol / 1 h / -78 °C 6.1: aq. AcOH / tetrahydrofuran / 2.5 h / 40 °C 7.1: 1.0 M aq. NaOH / methanol; tetrahydrofuran / 2 h / 20 °C View Scheme

1: PPTS / CH2Cl2 / Ambient temperature 2: TBAF / tetrahydrofuran / Ambient temperature 3: PCC, 4 Angstroem molecular sieves, NaOAc / CH2Cl2 / 0 °C 4: NaH / tetrahydrofuran / Ambient temperature 5: 92 percent / (S)-binaphthol, LiAlH4 / ethanol; tetrahydrofuran / -100 - -78 °C 6: 93 percent / acetic acid / H2O; tetrahydrofuran / 40 °C 7: 95 percent / 1N NaOH / methanol; tetrahydrofuran / Ambient temperature View Scheme

<b>Multi-step reaction with 18 steps<br /> </b>1.1: CuCN / tetrahydrofuran; diethyl ether / 1 h / -30 &deg;C<br />1.2: tetrahydrofuran; diethyl ether / 8 h / -12 &deg;C<br />2.1: pyridinium p-toluenesulfonate / CHCl₃ / 12 h / 20 &deg;C<br />3.1: O₃ / CH₂Cl₂ / -78 &deg;C<br />3.2: Ph₃P / CH₂Cl₂ / 12 h / 20 &deg;C<br />4.1: benzene / 7 h / 65 &deg;C<br />5.1: DIBAL-H / toluene; hexane / 1 h / -78 &deg;C<br />6.1: PCC; NaOAc; molecular sieves 4 Angstroem / CH₂Cl₂ / 1 h / 0 &deg;C<br />7.1: BuLi / tetrahydrofuran; hexane / 0.25 h / 0 &deg;C<br />7.2: tetrahydrofuran; hexane / 3 h / -78 - 0 &deg;C<br />8.1: tetrabutylammonium fluoride / tetrahydrofuran / 2 h / 20 &deg;C<br />9.1: Dess-Martin reagent / CH₂Cl₂ / 1 h / 0 &deg;C<br />10.1: Ni(cod)2; PPh₃; i-Bu₂-ALAC / toluene / 2 h / 0 &deg;C<br />11.1: imidazole / dimethylformamide / 7 h / 20 &deg;C<br />12.1: O₃; O₂ / CH₂Cl₂ / -78 &deg;C<br />12.2: PPh₃ / CH₂Cl₂ / 12 h / 20 &deg;C<br />13.1: potassium tert-butoxide / tetrahydrofuran / 1 h / 20 &deg;C<br />13.2: tetrahydrofuran / 0.25 h<br />14.1: methanol; diethyl ether / 0 &deg;C<br />15.1: tetrabutylammonium fluoride / tetrahydrofuran / 3 h / 20 &deg;C<br />16.1: DMAP; pyridine / CH₂Cl₂ / 2 h / 20 &deg;C<br />17.1: Dowex₅₀^W / methanol / 0.5 h / 50 &deg;C<br />18.1: Et₃N; DMAP / CH₂Cl₂ / 36 h / 20 &deg;C<br /> <br /> &nbsp;

<b>Multi-step reaction with 16 steps<br /> </b>1.1: O₃ / CH₂Cl₂ / -78 &deg;C<br />1.2: Ph₃P / CH₂Cl₂ / 12 h / 20 &deg;C<br />2.1: benzene / 7 h / 65 &deg;C<br />3.1: DIBAL-H / toluene; hexane / 1 h / -78 &deg;C<br />4.1: PCC; NaOAc; molecular sieves 4 Angstroem / CH₂Cl₂ / 1 h / 0 &deg;C<br />5.1: BuLi / tetrahydrofuran; hexane / 0.25 h / 0 &deg;C<br />5.2: tetrahydrofuran; hexane / 3 h / -78 - 0 &deg;C<br />6.1: tetrabutylammonium fluoride / tetrahydrofuran / 2 h / 20 &deg;C<br />7.1: Dess-Martin reagent / CH₂Cl₂ / 1 h / 0 &deg;C<br />8.1: Ni(cod)2; PPh₃; i-Bu₂-ALAC / toluene / 2 h / 0 &deg;C<br />9.1: imidazole / dimethylformamide / 7 h / 20 &deg;C<br />10.1: O₃; O₂ / CH₂Cl₂ / -78 &deg;C<br />10.2: PPh₃ / CH₂Cl₂ / 12 h / 20 &deg;C<br />11.1: potassium tert-butoxide / tetrahydrofuran / 1 h / 20 &deg;C<br />11.2: tetrahydrofuran / 0.25 h<br />12.1: methanol; diethyl ether / 0 &deg;C<br />13.1: tetrabutylammonium fluoride / tetrahydrofuran / 3 h / 20 &deg;C<br />14.1: DMAP; pyridine / CH₂Cl₂ / 2 h / 20 &deg;C<br />15.1: Dowex₅₀^W / methanol / 0.5 h / 50 &deg;C<br />16.1: Et₃N; DMAP / CH₂Cl₂ / 36 h / 20 &deg;C<br /> <br /> &nbsp;

<b>Multi-step reaction with 13 steps<br /> </b>1.1: PCC; NaOAc; molecular sieves 4 Angstroem / CH₂Cl₂ / 1 h / 0 &deg;C<br />2.1: BuLi / tetrahydrofuran; hexane / 0.25 h / 0 &deg;C<br />2.2: tetrahydrofuran; hexane / 3 h / -78 - 0 &deg;C<br />3.1: tetrabutylammonium fluoride / tetrahydrofuran / 2 h / 20 &deg;C<br />4.1: Dess-Martin reagent / CH₂Cl₂ / 1 h / 0 &deg;C<br />5.1: Ni(cod)2; PPh₃; i-Bu₂-ALAC / toluene / 2 h / 0 &deg;C<br />6.1: imidazole / dimethylformamide / 7 h / 20 &deg;C<br />7.1: O₃; O₂ / CH₂Cl₂ / -78 &deg;C<br />7.2: PPh₃ / CH₂Cl₂ / 12 h / 20 &deg;C<br />8.1: potassium tert-butoxide / tetrahydrofuran / 1 h / 20 &deg;C<br />8.2: tetrahydrofuran / 0.25 h<br />9.1: methanol; diethyl ether / 0 &deg;C<br />10.1: tetrabutylammonium fluoride / tetrahydrofuran / 3 h / 20 &deg;C<br />11.1: DMAP; pyridine / CH₂Cl₂ / 2 h / 20 &deg;C<br />12.1: Dowex₅₀^W / methanol / 0.5 h / 50 &deg;C<br />13.1: Et₃N; DMAP / CH₂Cl₂ / 36 h / 20 &deg;C<br /> <br /> &nbsp;

<b>Multi-step reaction with 14 steps<br /> </b>1.1: DIBAL-H / toluene; hexane / 1 h / -78 &deg;C<br />2.1: PCC; NaOAc; molecular sieves 4 Angstroem / CH₂Cl₂ / 1 h / 0 &deg;C<br />3.1: BuLi / tetrahydrofuran; hexane / 0.25 h / 0 &deg;C<br />3.2: tetrahydrofuran; hexane / 3 h / -78 - 0 &deg;C<br />4.1: tetrabutylammonium fluoride / tetrahydrofuran / 2 h / 20 &deg;C<br />5.1: Dess-Martin reagent / CH₂Cl₂ / 1 h / 0 &deg;C<br />6.1: Ni(cod)2; PPh₃; i-Bu₂-ALAC / toluene / 2 h / 0 &deg;C<br />7.1: imidazole / dimethylformamide / 7 h / 20 &deg;C<br />8.1: O₃; O₂ / CH₂Cl₂ / -78 &deg;C<br />8.2: PPh₃ / CH₂Cl₂ / 12 h / 20 &deg;C<br />9.1: potassium tert-butoxide / tetrahydrofuran / 1 h / 20 &deg;C<br />9.2: tetrahydrofuran / 0.25 h<br />10.1: methanol; diethyl ether / 0 &deg;C<br />11.1: tetrabutylammonium fluoride / tetrahydrofuran / 3 h / 20 &deg;C<br />12.1: DMAP; pyridine / CH₂Cl₂ / 2 h / 20 &deg;C<br />13.1: Dowex₅₀^W / methanol / 0.5 h / 50 &deg;C<br />14.1: Et₃N; DMAP / CH₂Cl₂ / 36 h / 20 &deg;C<br /> <br /> &nbsp;

<b>Multi-step reaction with 4 steps<br /> </b>1: 54 percent / Ni(cod)2; PPh₃; 1,3-cyclohexadiene / iBu₂-ALAC / tetrahydrofuran / 6 h / 25 &deg;C<br />2: DMAP; pyridine / CH₂Cl₂ / 2 h / 20 &deg;C<br />3: Dowex₅₀^W / methanol / 0.5 h / 50 &deg;C<br />4: Et₃N; DMAP / CH₂Cl₂ / 36 h / 20 &deg;C<br /> <br /> &nbsp;

<b>Multi-step reaction with 5 steps<br /> </b>1: Dess-Martin reagent / CH₂Cl₂ / 2 h / 0 &deg;C<br />2: 54 percent / Ni(cod)2; PPh₃; 1,3-cyclohexadiene / iBu₂-ALAC / tetrahydrofuran / 6 h / 25 &deg;C<br />3: DMAP; pyridine / CH₂Cl₂ / 2 h / 20 &deg;C<br />4: Dowex₅₀^W / methanol / 0.5 h / 50 &deg;C<br />5: Et₃N; DMAP / CH₂Cl₂ / 36 h / 20 &deg;C<br /> <br /> &nbsp;