1: 97.4 percent / LiBH4 / tetrahydrofuran / Ambient temperature 2: 87.7 percent / Et3N / CH2Cl2; tetrahydrofuran / 43 h / Ambient temperature 3: 41.7 percent / triphenylphosphine, DEAD / tetrahydrofuran / 21.6 h / Ambient temperature 4: 97.3 percent / ammonia / methanol / 60 h / 85 - 87 °C 5: 0.19 percent / trifluoroacetic acid / 1.25 h / Ambient temperature View Scheme

lithium borohydride in tetrahydrofuran Ambient temperature;