1: 97 percent 2: 96 percent / DABCO, Et2NH 3: 98 percent / (benzotriazol-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate, DIEA 4: 93 percent / LiOH 5: 62 percent / DIAD, PPh3, TsOH*H2O / tetrahydrofuran / 2 h / 0 °C 6: 84 percent / I2 / methanol; H2O View Scheme