1: 0.01 N HCl / methanol; H2O / 2 h / 105 °C 2: Bu4NBr, 9 M aq. HBr / 0.75 h / 110 °C View Scheme

<b>Multi-step reaction with 8 steps<br /> </b>1: 1.) Et₃N, trimethylaluminum / 1.) CH₂Cl₂, RT, 15 min, 2.) CH₂Cl₂, reflux, 48 h<br />2: Jones reagent / acetone / 2 h / 0 - 20 &deg;C<br />3: benzene / 2.5 h / Heating<br />4: 83 percent / Et₄NOTS / methanol / anodic oxidation, carbon rod anode, Pt cathode<br />5: TiCl₄ / CH₂Cl₂ / 36 h / Ambient temperature<br />6: 1.) O₃, 2.) Zn-dust, HOAc / 1.) MeOH, -78 deg C, 0.5 h, 2.) MeOH, RT, 48 h<br />7: 38 percent / Et₃N / benzene / 0 &deg;C<br />8: 55 percent / 2,3-dichloro-4,5-dicyanobenzoquinone / dioxane / 3 h / Heating<br /> <br /> &nbsp;

<b>Multi-step reaction with 5 steps<br /> </b>1: 83 percent / Et₄NOTS / methanol / anodic oxidation, carbon rod anode, Pt cathode<br />2: TiCl₄ / CH₂Cl₂ / 36 h / Ambient temperature<br />3: 1.) O₃, 2.) Zn-dust, HOAc / 1.) MeOH, -78 deg C, 0.5 h, 2.) MeOH, RT, 48 h<br />4: 38 percent / Et₃N / benzene / 0 &deg;C<br />5: 55 percent / 2,3-dichloro-4,5-dicyanobenzoquinone / dioxane / 3 h / Heating<br /> <br /> &nbsp;

<b>Multi-step reaction with 9 steps<br /> </b>1: 1.) LDA / 1.) THF, hexane, -45 deg C, 1.5 h, 2.) THF, hexane, -45 deg C, 4.5 h<br />2: 1.) Et₃N, trimethylaluminum / 1.) CH₂Cl₂, RT, 15 min, 2.) CH₂Cl₂, reflux, 48 h<br />3: Jones reagent / acetone / 2 h / 0 - 20 &deg;C<br />4: benzene / 2.5 h / Heating<br />5: 83 percent / Et₄NOTS / methanol / anodic oxidation, carbon rod anode, Pt cathode<br />6: TiCl₄ / CH₂Cl₂ / 36 h / Ambient temperature<br />7: 1.) O₃, 2.) Zn-dust, HOAc / 1.) MeOH, -78 deg C, 0.5 h, 2.) MeOH, RT, 48 h<br />8: 38 percent / Et₃N / benzene / 0 &deg;C<br />9: 55 percent / 2,3-dichloro-4,5-dicyanobenzoquinone / dioxane / 3 h / Heating<br /> <br /> &nbsp;