1.1: lithium diisopropyl amide / tetrahydrofuran / -78 °C 2.1: sodium hydroxide / ethanol / Reflux 3.1: sodium hydroxide / N,N-dimethyl-formamide / 1 h / 20 °C / Inert atmosphere 3.2: 2 h / 20 °C / Inert atmosphere 4.1: sodium hydroxide / N,N-dimethyl-formamide / 2 h / 60 °C / Inert atmosphere 5.1: hydrogenchloride / ethanol; water / 6 h / 90 °C View Scheme

1.1: LDA / tetrahydrofuran; hexane / 0.5 h / -78 °C 1.2: 70 percent / C2Cl6 / tetrahydrofuran; hexane / -78 - 20 °C 2.1: NaOH / ethanol / Heating View Scheme

1: With lithium diisopropyl amide in tetrahydrofuran; hexane T=-78°C; 0.5 h; 2: With iodine in tetrahydrofuran; hexane T=-78 - 20°C;

1: With lithium diisopropyl amide in tetrahydrofuran; hexane T=-78°C; 0.5 h; 2: With ethylene dibromide in tetrahydrofuran; hexane T=-78 - 20°C;

1: With lithium diisopropyl amide in tetrahydrofuran; hexane T=-78°C; 0.5 h; 2: With 1,2,2-trichloro-1,1,2-trichloro-ethane in tetrahydrofuran; hexane T=-78 - 20°C;

1.1: LDA / tetrahydrofuran; hexane / 0.5 h / -78 °C 1.2: 60 percent / 1,2-dibromoethane / tetrahydrofuran; hexane / -78 - 20 °C 2.1: 70 percent / NaOH / ethanol / Heating View Scheme

1.1: LDA / tetrahydrofuran; hexane / 0.5 h / -78 °C 1.2: 74 percent / iodine / tetrahydrofuran; hexane / -78 - 20 °C 2.1: 82 percent / NaOH / ethanol / Heating View Scheme