1: 75 percent / diethyl phosphorocyanidate, Et3N / dimethylformamide 2: dimethylformamide / 145 °C 4: 80 percent / diisobutylaluminum hydride / diethyl ether 5: 82 percent / tetrahydrofuran 6: 1) H2; 2) aq. HF / 1) Pd-C View Scheme