1.1: n-BuLi / tetrahydrofuran / 2 h / -78 °C 1.2: 97 percent / tetrahydrofuran / 6 h / 20 °C 2.1: 89 percent / KOH / H2O; dioxane / 24 h / Heating 3.1: trifluoroacetic acid / CH2Cl2 / 2 h / 20 °C View Scheme

<b>Multi-step reaction with 2 steps<br /> </b>1.1: 83 percent / triethylamine / CH₂Cl₂ / 24 h / 20 &deg;C<br />2.1: (-)-sparteine; sec-BuLi / various solvent(s); tetrahydrofuran; cyclohexane / 1 h / -78 &deg;C<br />2.2: various solvent(s); tetrahydrofuran; cyclohexane / 1 h / -78 &deg;C<br /> <br /> &nbsp;