1: Et3N / p-toluenesulfonic acid / CH2Cl2 / 0.17 h / Ambient temperature 2: K2CO3 / methanol / 1 h / 45 °C 3: triphenylphosphine, diethyl azodicarboxylate / benzene / 2 h / Ambient temperature 4: p-toluenesulfonic acid, Et3N / methanol / 1 h / Ambient temperature 5: NaN3, dimethylsulfoxide / 19 h / 45 °C 6: toluene / 20 h / 70 °C View Scheme

<b>Multi-step reaction with 3 steps<br /> </b>1: 81 percent / sodium hydride / tetrahydrofuran / 1 h / Ambient temperature<br />2: 92 percent / 65percent aq. acetic acid / tetrahydrofuran / 1.5 h / 40 &deg;C<br />3: diisobutylaluminum 2,6-di-tert-butyl-4-methylphenoxide / toluene / 1.) -78 deg C, 15 min; 2.) -20 deg C, 2 h<br /> <br /> &nbsp;

<b>Multi-step reaction with 4 steps<br /> </b>1: 1.) n-BuLi / 1.) THF, hexane, -78 deg C, 15 min; 2.) THF, hexane, -78 deg C, 2.5 h<br />2: 81 percent / sodium hydride / tetrahydrofuran / 1 h / Ambient temperature<br />3: 92 percent / 65percent aq. acetic acid / tetrahydrofuran / 1.5 h / 40 &deg;C<br />4: diisobutylaluminum 2,6-di-tert-butyl-4-methylphenoxide / toluene / 1.) -78 deg C, 15 min; 2.) -20 deg C, 2 h<br /> <br /> &nbsp;

<b>Multi-step reaction with 3 steps<br /> </b>1: 81 percent / sodium hydride / tetrahydrofuran / 1 h / Ambient temperature<br />2: 92 percent / 65percent aq. acetic acid / tetrahydrofuran / 1.5 h / 40 &deg;C<br />3: diisobutylaluminum 2,6-di-tert-butyl-4-methylphenoxide / toluene / 1.) -78 deg C, 15 min; 2.) -20 deg C, 2 h<br /> <br /> &nbsp;