1.1: 67 percent / KOH / methanol / 2.5 h / 20 °C 2.1: n-butyllithium / hexane; tetrahydrofuran / 2 h / -25 °C 2.2: 65 percent / tetrahydrofuran; CH2Cl2 / 20 °C View Scheme

potassium hydroxide in methanol T=20°C; 2.5 h;