1: 56 percent / DMAP / CH2Cl2 / 1) -10 to 0 deg C, 2 h, 2) 4 deg C, 1 h 2: 76 percent / NaN3 / dimethylformamide / 1) 50 deg C, 2 h, 2) 70 deg C, 1 h View Scheme