1.1: 51 percent / p-TsOH / CH2Cl2 / 2.3 h / 20 °C 2.1: 75 percent / p-TsOH; N-(phenylseleno)phthalimide / CH2Cl2 / 6.5 h / 20 °C 3.1: 60 percent / 4-(dimethylamino)pyridine / pyridine / 24 h / 40 °C 4.1: ozone / CH2Cl2 / -78 °C 4.2: 62 percent / pyridine / CH2Cl2; CCl4 / 1.5 h / Heating View Scheme

<b>Multi-step reaction with 2 steps<br /> </b>1: 100 percent / tetrabutylammonium fluoride / tetrahydrofuran / 2.5 h / 20 &deg;C<br />2: 54 percent / imidazole; iodine; triphenylphosphine / 2,6-lutidine / benzene; 1,2-dichloro-ethane; H₂O / 0.25 h / 80 &deg;C<br /> <br /> &nbsp;