1.1: tetrahydrofuran / 3 h / 70 °C 1.2: 58 percent / KH / tetrahydrofuran / 3 h / 50 °C 2.1: 74 percent / 4-(dimethylamino)pyridine; 2,4,6-collidine / CH2Cl2 / 3 h / 20 °C 3.1: 41 percent / CuCN / tetrahydrofuran; diethyl ether / 1 h / 0 °C 4.1: 80 percent / hydrochloric acid / tetrahydrofuran; H2O / 30 h / 20 °C View Scheme