1.1: n-butyllithium / tetrahydrofuran; cyclohexane / 0.25 h / -78 °C / |Schlenk technique; |Inert atmosphere 1.2: 0.25 h / -78 °C / |Schlenk technique; |Inert atmosphere 2.1: potassium hydrogensulfate / anhydrous xylene / 1 h / 150 °C 3.1: boron trichloride / dichloromethane / 0 °C / |Inert atmosphere 3.2: polyphosphoric acid / 3 h / 40 - 130 °C / |Inert atmosphere 4.1: potassium permanganate / acetone / 3 h / 0 °C View Scheme

1.1: potassium hydrogensulfate / anhydrous xylene / 1 h / 150 °C 2.1: boron trichloride / dichloromethane / 0 °C / |Inert atmosphere 2.2: polyphosphoric acid / 3 h / 40 - 130 °C / |Inert atmosphere 3.1: potassium permanganate / acetone / 3 h / 0 °C View Scheme

1.1: boron trichloride / dichloromethane / 0 °C / |Inert atmosphere 1.2: polyphosphoric acid / 3 h / 40 - 130 °C / |Inert atmosphere 2.1: potassium permanganate / acetone / 3 h / 0 °C View Scheme