1: 77 percent / LiHMDS / tetrahydrofuran / -78 - 20 °C 2: 65 percent / NBS; benzoyl peroxide / CCl4 / Heating View Scheme

water; potassium carbonate in methanol 3 h; Heating;

1.1: 95 percent / benzyltriethylammonium chloride; NaOH / CH2Cl2 / 0 - 20 °C 2.1: LDA / tetrahydrofuran / 0.67 h / -30 °C 2.2: 85 percent / tetrahydrofuran / 16 h / 20 °C 3.1: 81 percent / NBS / CCl4 / 12 h / 20 °C 4.1: 57 percent / K2CO3; H2O / methanol / 3 h / Heating View Scheme

1.1: LDA / tetrahydrofuran / 0.67 h / -30 °C 1.2: 85 percent / tetrahydrofuran / 16 h / 20 °C 2.1: 81 percent / NBS / CCl4 / 12 h / 20 °C 3.1: 57 percent / K2CO3; H2O / methanol / 3 h / Heating View Scheme

1: 81 percent / NBS / CCl4 / 12 h / 20 °C 2: 57 percent / K2CO3; H2O / methanol / 3 h / Heating View Scheme

lithium hexamethyldisilazane in tetrahydrofuran T=-78 - 20°C;