1.1: sec.-butyllithium / tetrahydrofuran; hexane; cyclohexane / 1 h / -78 °C / Inert atmosphere 1.2: 1 h / -78 °C / Inert atmosphere 1.3: 24 h / 20 °C 2.1: Pearlman's catalist; hydrogen / tetrahydrofuran; methanol / 20 °C 3.1: trifluoroacetic anhydride / dichloromethane / 5 h / 0 - 20 °C / Inert atmosphere 3.2: 3.5 h / 20 °C 4.1: aluminium(III) iodide; tetra-(n-butyl)ammonium iodide / benzene / 12 h / Reflux; Inert atmosphere View Scheme