1.1: potassium tert-butylate / tetrahydrofuran / 0.17 h / 20 °C / Inert atmosphere 1.2: 4.25 h / 20 °C / Inert atmosphere 1.3: 2 h / 50 °C / Inert atmosphere 2.1: sodium carbonate / dichloromethane; water 2.2: 18 h / 70 °C / Inert atmosphere 3.1: pyridine / 3.25 h / -15 - 5 °C / Inert atmosphere 4.1: potassium carbonate / acetonitrile / 3.5 h / 80 °C / Inert atmosphere 5.1: potassium hydroxide / 3-methyl pentan-3-ol / 18 h / 120 °C / Inert atmosphere 6.1: boron tribromide / dichloromethane / 2 h / 0 - 20 °C / Inert atmosphere View Scheme