1: 92 percent / CF3COOH / CH2Cl2 / 0.5 h / 0 - 20 °C 2: CF3COOH / CH2Cl2 / 0.25 h / Ambient temperature 3: I2, AcOK / ethanol / 2 h / Heating View Scheme

<b>Multi-step reaction with 2 steps<br /> </b>1: 88 percent / tetrahydrofuran / 4 h / Ambient temperature<br />2: 1.) sec-BuLi / 1.) THF, cyclohexane, -30 deg C, 10 min, 2.) THF, cyclohexane, from -60 to -30 deg C, 0.5 h<br /> <br /> &nbsp;