toluene-4-sulfonic acid 1.) dioxan, water; 2.) t-butylmethyl ether, irradiation; Yield given. Multistep reaction;

<b>Multi-step reaction with 8 steps<br /> </b>1: 82 percent / PCC / CH₂Cl₂ / 3 h / Ambient temperature<br />2: 1.) t-BuOK / 1.) THF, room temperature, 2 h, 2.) 30 min<br />3: 93 percent / Na₂CO₃ / methanol / 3.5 h / Ambient temperature<br />4: 48 percent / SeO₂, t-BuOOH / 2,2,4-trimethyl-pentane / 1.) 0 deg C, 2 h, 2.) room temperature, 4 h<br />5: 94 percent / imidazole / dimethylformamide / 4 h / Ambient temperature<br />6: 1.) n-BuLi / 1.) THF, hexane, room temperature, 20 min, 2.) room temperature, 30 min<br />7: 88 percent / MeONa, LiAlH₄ / methanol; tetrahydrofuran / 1 h / Heating<br />8: 99 percent / TBAF / tetrahydrofuran / 16 h / Ambient temperature<br /> <br /> &nbsp;

<b>Multi-step reaction with 6 steps<br /> </b>1: 93 percent / Na₂CO₃ / methanol / 3.5 h / Ambient temperature<br />2: 48 percent / SeO₂, t-BuOOH / 2,2,4-trimethyl-pentane / 1.) 0 deg C, 2 h, 2.) room temperature, 4 h<br />3: 94 percent / imidazole / dimethylformamide / 4 h / Ambient temperature<br />4: 1.) n-BuLi / 1.) THF, hexane, room temperature, 20 min, 2.) room temperature, 30 min<br />5: 88 percent / MeONa, LiAlH₄ / methanol; tetrahydrofuran / 1 h / Heating<br />6: 99 percent / TBAF / tetrahydrofuran / 16 h / Ambient temperature<br /> <br /> &nbsp;

<b>Multi-step reaction with 9 steps<br /> </b>1: 67 percent / Sm, HgCl₂ / tetrahydrofuran / 31 - 40 &deg;C<br />2: 82 percent / PCC / CH₂Cl₂ / 3 h / Ambient temperature<br />3: 1.) t-BuOK / 1.) THF, room temperature, 2 h, 2.) 30 min<br />4: 93 percent / Na₂CO₃ / methanol / 3.5 h / Ambient temperature<br />5: 48 percent / SeO₂, t-BuOOH / 2,2,4-trimethyl-pentane / 1.) 0 deg C, 2 h, 2.) room temperature, 4 h<br />6: 94 percent / imidazole / dimethylformamide / 4 h / Ambient temperature<br />7: 1.) n-BuLi / 1.) THF, hexane, room temperature, 20 min, 2.) room temperature, 30 min<br />8: 88 percent / MeONa, LiAlH₄ / methanol; tetrahydrofuran / 1 h / Heating<br />9: 99 percent / TBAF / tetrahydrofuran / 16 h / Ambient temperature<br /> <br /> &nbsp;

<b>Multi-step reaction with 5 steps<br /> </b>1: 48 percent / SeO₂, t-BuOOH / 2,2,4-trimethyl-pentane / 1.) 0 deg C, 2 h, 2.) room temperature, 4 h<br />2: 94 percent / imidazole / dimethylformamide / 4 h / Ambient temperature<br />3: 1.) n-BuLi / 1.) THF, hexane, room temperature, 20 min, 2.) room temperature, 30 min<br />4: 88 percent / MeONa, LiAlH₄ / methanol; tetrahydrofuran / 1 h / Heating<br />5: 99 percent / TBAF / tetrahydrofuran / 16 h / Ambient temperature<br /> <br /> &nbsp;

<b>Multi-step reaction with 6 steps<br /> </b>1: 1.) t-BuOK / 1.) THF, room temperature, 30 min, 2.) 1 h<br />2: 48 percent / SeO₂, t-BuOOH / 2,2,4-trimethyl-pentane / 1.) 0 deg C, 2 h, 2.) room temperature, 4 h<br />3: 94 percent / imidazole / dimethylformamide / 4 h / Ambient temperature<br />4: 1.) n-BuLi / 1.) THF, hexane, room temperature, 20 min, 2.) room temperature, 30 min<br />5: 88 percent / MeONa, LiAlH₄ / methanol; tetrahydrofuran / 1 h / Heating<br />6: 99 percent / TBAF / tetrahydrofuran / 16 h / Ambient temperature<br /> <br /> &nbsp;

<b>Multi-step reaction with 7 steps<br /> </b>1: 80 percent / p-TsOH / acetone; H₂O / 48 h / Heating<br />2: 1.) t-BuOK / 1.) THF, room temperature, 30 min, 2.) 1 h<br />3: 48 percent / SeO₂, t-BuOOH / 2,2,4-trimethyl-pentane / 1.) 0 deg C, 2 h, 2.) room temperature, 4 h<br />4: 94 percent / imidazole / dimethylformamide / 4 h / Ambient temperature<br />5: 1.) n-BuLi / 1.) THF, hexane, room temperature, 20 min, 2.) room temperature, 30 min<br />6: 88 percent / MeONa, LiAlH₄ / methanol; tetrahydrofuran / 1 h / Heating<br />7: 99 percent / TBAF / tetrahydrofuran / 16 h / Ambient temperature<br /> <br /> &nbsp;

<b>Multi-step reaction with 8 steps<br /> </b>1: 1.) t-BuOK / 1.) THF, -70 deg C, 15 min, 2.) -78 deg C, 30 min; -78 deg C -&gt; room temperature<br />2: 80 percent / p-TsOH / acetone; H₂O / 48 h / Heating<br />3: 1.) t-BuOK / 1.) THF, room temperature, 30 min, 2.) 1 h<br />4: 48 percent / SeO₂, t-BuOOH / 2,2,4-trimethyl-pentane / 1.) 0 deg C, 2 h, 2.) room temperature, 4 h<br />5: 94 percent / imidazole / dimethylformamide / 4 h / Ambient temperature<br />6: 1.) n-BuLi / 1.) THF, hexane, room temperature, 20 min, 2.) room temperature, 30 min<br />7: 88 percent / MeONa, LiAlH₄ / methanol; tetrahydrofuran / 1 h / Heating<br />8: 99 percent / TBAF / tetrahydrofuran / 16 h / Ambient temperature<br /> <br /> &nbsp;