boron tribromide in dichloromethane T=-35 - 0°C;

<b>Multi-step reaction with 5 steps<br /> </b>1.1: 85 percent / aluminum chloride / 1,2-dichloro-benzene / 6 h / 83 &deg;C<br />2.1: 82 percent / KOH; hydrazine monohydrate / triethylene glycol / 90 - 200 &deg;C<br />3.1: 75 percent / polyphosphoric acid / 1 h / 80 &deg;C<br />4.1: p-toluenesulfonic acid monohydrate; trimethyl orthoformate / methanol; benzene / 40 h / Heating<br />4.2: 75 percent / p-toluenesulfonic acid monohydrate / benzene / 4 h / Heating<br />5.1: n-BuLi / tetrahydrofuran; pentane / 0.67 h / -78 &deg;C<br />5.2: 78 percent / tetrahydrofuran; pentane / 1.25 h / cooling<br /> <br /> &nbsp;

<b>Multi-step reaction with 2 steps<br /> </b>1.1: p-toluenesulfonic acid monohydrate; trimethyl orthoformate / methanol; benzene / 40 h / Heating<br />1.2: 75 percent / p-toluenesulfonic acid monohydrate / benzene / 4 h / Heating<br />2.1: n-BuLi / tetrahydrofuran; pentane / 0.67 h / -78 &deg;C<br />2.2: 78 percent / tetrahydrofuran; pentane / 1.25 h / cooling<br /> <br /> &nbsp;