sodium hydroxide in ethanol T=20°C; 4 h;

1.1: n-BuLi / hexane; tetrahydrofuran / 1.5 h / -70 °C 1.2: 65 percent / hexane; tetrahydrofuran / 0.25 h / -70 °C 2.1: 100 percent / NaOH / ethanol / 4 h / 20 °C View Scheme

1.1: NaOMe / methanol / 19 h / Heating 2.1: 60 percent / AcOH / ethanol / 0.5 h / Heating 3.1: n-BuLi / hexane; tetrahydrofuran / 1.5 h / -70 °C 3.2: 65 percent / hexane; tetrahydrofuran / 0.25 h / -70 °C 4.1: 100 percent / NaOH / ethanol / 4 h / 20 °C View Scheme

1.1: 60 percent / AcOH / ethanol / 0.5 h / Heating 2.1: n-BuLi / hexane; tetrahydrofuran / 1.5 h / -70 °C 2.2: 65 percent / hexane; tetrahydrofuran / 0.25 h / -70 °C 3.1: 100 percent / NaOH / ethanol / 4 h / 20 °C View Scheme