1: 92 percent / DIBAL / CH2Cl2 / -78 °C 2: 87 percent / PPTS / methanol 3: 96 percent / Bu4NF / tetrahydrofuran 4: 1.) BuLi / 1.) THF, -78 deg C 5: toluene / Irradiation 6: 1.) O3, 2.) Me2S / 1.) CH2Cl2, -78 deg C 7: 79 percent / NaH / tetrahydrofuran 8: 1.) HCl, 2.) DBU / 1.) CH2Cl2, MeOH, 2.) toluene, reflux 9: 76 percent / Na(Hg), Na2HPO4 / methanol / 0.17 h / -40 °C View Scheme

<b>Multi-step reaction with 2 steps<br /> </b>1.1: 99 percent / imidazole / dimethylformamide / 24 h / 20 &deg;C<br />2.1: LiHMDS / tetrahydrofuran; hexane / 1 h / -20 &deg;C<br />2.2: 98 percent / tetrahydrofuran; hexane / -20 - 20 &deg;C<br /> <br /> &nbsp;

<b>Multi-step reaction with 2 steps<br /> </b>1.1: 99 percent / imidazole / dimethylformamide / 24 h / 20 &deg;C<br />2.1: LiHMDS / tetrahydrofuran; hexane / 1 h / -20 &deg;C<br />2.2: 98 percent / tetrahydrofuran; hexane / -20 - 20 &deg;C<br /> <br /> &nbsp;

<b>Multi-step reaction with 3 steps<br /> </b>1.1: SOCl₂ / methanol<br />1.2: NaBH₄ / ethanol<br />2.1: 99 percent / imidazole / dimethylformamide / 24 h / 20 &deg;C<br />3.1: LiHMDS / tetrahydrofuran; hexane / 1 h / -20 &deg;C<br />3.2: 98 percent / tetrahydrofuran; hexane / -20 - 20 &deg;C<br /> <br /> &nbsp;

<b>Multi-step reaction with 3 steps<br /> </b>1: 85 percent / NaBH₄ / ethanol / 2 h / Ambient temperature<br />2: 72 percent / imidazole, DMAP / CH₂Cl₂ / Ambient temperature<br />3: 75 percent / lithium hexamethyldisilazide / tetrahydrofuran / 60 h / Ambient temperature<br /> <br /> &nbsp;