ammonium cerium(IV) nitrate; silica gel in dichloromethane T=25°C; detritylation; 1.5 h;

1: 43 percent / DBU / acetonitrile / 15 h / Ambient temperature 2: 65 percent / DMAP / acetonitrile / 20 h / Ambient temperature 3: AIBN, Bu3SnH / toluene / 3 h / 85 °C 4: TBAF / tetrahydrofuran / 4 h / 75 °C 5: 81 percent / ZnBr2 / CH2Cl2; methanol / 0.33 h View Scheme

1: 1.) MsCl, pyridine 2.) 1 M NaOH / 1.) RT, 2.) dioxane, RT, 3 h 2: 97 percent / Me3SiOTf, Al2O3 / methanol View Scheme

1: 43 percent / DBU / acetonitrile / 15 h / Ambient temperature 2: 65 percent / DMAP / acetonitrile / 20 h / Ambient temperature 3: AIBN, Bu3SnH / toluene / 3 h / 85 °C 4: TBAF / tetrahydrofuran / 4 h / 75 °C 5: 81 percent / ZnBr2 / CH2Cl2; methanol / 0.33 h 6: 80 percent / pyridine / 20 h / Ambient temperature 7: 69 percent / o-chlorophenylphosphorodichloridate / pyridine / 48 h / Ambient temperature 8: 75 percent / NH4OH / dioxane / 2.5 h / Ambient temperature 9: 82 percent / NaOEt / 24 h / Ambient temperature 10: 77 percent / methanol / 4 h / Heating View Scheme

1: 43 percent / DBU / acetonitrile / 15 h / Ambient temperature 2: 65 percent / DMAP / acetonitrile / 20 h / Ambient temperature 3: AIBN, Bu3SnH / toluene / 3 h / 85 °C 4: TBAF / tetrahydrofuran / 4 h / 75 °C 5: 81 percent / ZnBr2 / CH2Cl2; methanol / 0.33 h 6: 80 percent / pyridine / 20 h / Ambient temperature 7: 69 percent / o-chlorophenylphosphorodichloridate / pyridine / 48 h / Ambient temperature 8: 75 percent / NH4OH / dioxane / 2.5 h / Ambient temperature 9: 82 percent / NaOEt / 24 h / Ambient temperature View Scheme

1,8-diazabicyclo[5.4.0]undec-7-ene in acetonitrile

1: 43 percent / DBU / acetonitrile / 15 h / Ambient temperature 2: 65 percent / DMAP / acetonitrile / 20 h / Ambient temperature 3: AIBN, Bu3SnH / toluene / 3 h / 85 °C 4: TBAF / tetrahydrofuran / 4 h / 75 °C 5: 81 percent / ZnBr2 / CH2Cl2; methanol / 0.33 h 6: 80 percent / pyridine / 20 h / Ambient temperature 7: 69 percent / o-chlorophenylphosphorodichloridate / pyridine / 48 h / Ambient temperature 8: 75 percent / NH4OH / dioxane / 2.5 h / Ambient temperature 9: 82 percent / NaOEt / 24 h / Ambient temperature 10: 77 percent / methanol / 4 h / Heating 11: 78 percent / pyridine / 2 h View Scheme

1,8-diazabicyclo[5.4.0]undec-7-ene in acetonitrile

1: (i) Py, (ii) K2CO3, acetone 2: NaN3, NH4Cl / dimethylformamide 3: HCl / diethyl ether; CHCl3; dioxane View Scheme

1: 77 percent / tetrahydrofuran / 72 h / Ambient temperature 2: 45 percent / triethyl phosphite / 1 h / 160 °C 3: 40 percent / p-toluenesulfonic acid / CHCl3; methanol / 0.75 h / Ambient temperature View Scheme