1: 86 percent / malonic acid / 24 h / 20 °C 2: 91 percent / potassium tert-butoxide / tetrahydrofuran / 2 h / 0 °C View Scheme

1: 86 percent / malonic acid / 24 h / 20 °C 2: 91 percent / potassium tert-butoxide / tetrahydrofuran / 2 h / 0 °C 3: 79 percent / oxalic acid dihydrate / H2O; ethanol / 2 h / 20 °C View Scheme

malonic acid T=20°C; 24 h;