1.1: i-PrMgCl; Ti(O-i-Pr)4 / diethyl ether / -78 - -50 °C 1.2: 51 percent / NBS / diethyl ether; tetrahydrofuran / -78 - 20 °C 2.1: 96 percent / imidazole / dimethylformamide / 12 h / 20 °C 3.1: DBU / toluene / 20 h / 70 °C 4.1: 1.16 g / Cs2CO3 / dimethylformamide / 12 h / 20 °C 5.1: aq. KOH; PdCl2(dppf) / tetrahydrofuran / 24 h / 60 °C 6.1: 68.3 mg / TBAF / tetrahydrofuran / 24 h / 20 °C View Scheme

<b>Multi-step reaction with 8 steps<br /> </b>1.1: n-BuLi / tetrahydrofuran; hexane / 1 h / -78 &deg;C<br />1.2: BF₃*Et₂O / tetrahydrofuran; hexane / -78 - 20 &deg;C<br />1.3: 82 percent / hydrochloric acid / tetrahydrofuran / 1 h / 20 &deg;C<br />2.1: 96 percent / porcine pancreatic lipase / 72 h / 20 &deg;C<br />3.1: imidazole / dimethylformamide / 12 h / 20 &deg;C<br />4.1: 27.8 g / Red-Al / diethyl ether; toluene / 1 h / 0 &deg;C<br />5.1: diisopropyl (L)-(+)-tartrate; Ti(O-i-Pr)4; t-BuOOH / CH₂Cl₂ / 24 h / -20 &deg;C<br />6.1: Et₃N / CH₂Cl₂ / 1 h / 0 &deg;C<br />7.1: NaI; NaHCO₃ / acetone / 20 h / 20 &deg;C<br />8.1: 21.7 g / Zn; AcOH / methanol / 1 h / sonication<br /> <br /> &nbsp;

<b>Multi-step reaction with 3 steps<br /> </b>1: Et₃N / CH₂Cl₂ / 1 h / 0 &deg;C<br />2: NaI; NaHCO₃ / acetone / 20 h / 20 &deg;C<br />3: 21.7 g / Zn; AcOH / methanol / 1 h / sonication<br /> <br /> &nbsp;

<b>Multi-step reaction with 7 steps<br /> </b>1: 96 percent / porcine pancreatic lipase / 72 h / 20 &deg;C<br />2: imidazole / dimethylformamide / 12 h / 20 &deg;C<br />3: 27.8 g / Red-Al / diethyl ether; toluene / 1 h / 0 &deg;C<br />4: diisopropyl (L)-(+)-tartrate; Ti(O-i-Pr)4; t-BuOOH / CH₂Cl₂ / 24 h / -20 &deg;C<br />5: Et₃N / CH₂Cl₂ / 1 h / 0 &deg;C<br />6: NaI; NaHCO₃ / acetone / 20 h / 20 &deg;C<br />7: 21.7 g / Zn; AcOH / methanol / 1 h / sonication<br /> <br /> &nbsp;