1.1: 98 percent / NH4OH / tetrahydrofuran / 2 h / 130 °C 2.1: 80 mg / PPh3; DIAD / tetrahydrofuran / 17 h / Heating 3.1: DIAD; TFA / CH2Cl2; H2O / 1.5 h / 20 °C 3.2: 1.7 mg / KOH / CH2Cl2; H2O / 0.5 h / Heating 4.1: 92 percent / Na; NH3 / diethyl ether / 5 h / -78 - 20 °C View Scheme