1: 99.5 percent / triphenylphosphine / tetrahydrofuran; H2O / Ambient temperature 2: 95 percent / pyridine / Ambient temperature 3: 72 percent / hydrochloric acid / tetrahydrofuran / 1 h / Heating 4: 66 percent / imidazole / dimethylformamide / 13 h / 60 °C 5: 89 percent / pyridine / 0.5 h / Ambient temperature 6: 90 percent / tetra-n-butylammonium fluoride / tetrahydrofuran / 0.5 h / Ambient temperature 7: 47 percent / 1,1,3,3-tetramethylurea, stannous triflate, 4A molecular sieves / CH2Cl2 / 16 h / Ambient temperature 8: 95 percent / sodium methoxide / methanol / 1 h / Ambient temperature View Scheme

1: 57 percent / sodium azide / dimethylformamide / 3 h / 90 °C 2: 99.5 percent / triphenylphosphine / tetrahydrofuran; H2O / Ambient temperature 3: 95 percent / pyridine / Ambient temperature 4: 72 percent / hydrochloric acid / tetrahydrofuran / 1 h / Heating 5: 66 percent / imidazole / dimethylformamide / 13 h / 60 °C 6: 89 percent / pyridine / 0.5 h / Ambient temperature 7: 90 percent / tetra-n-butylammonium fluoride / tetrahydrofuran / 0.5 h / Ambient temperature 8: 47 percent / 1,1,3,3-tetramethylurea, stannous triflate, 4A molecular sieves / CH2Cl2 / 16 h / Ambient temperature 9: 95 percent / sodium methoxide / methanol / 1 h / Ambient temperature View Scheme

1: diphenyldisulfide / cyclohexane; dioxane / 3 h / Irradiation 2: 99.4 percent / triethylamine / CH2Cl2 / 1.5 h / Ambient temperature 3: 57 percent / sodium azide / dimethylformamide / 3 h / 90 °C 4: 99.5 percent / triphenylphosphine / tetrahydrofuran; H2O / Ambient temperature 5: 95 percent / pyridine / Ambient temperature 6: 72 percent / hydrochloric acid / tetrahydrofuran / 1 h / Heating 7: 66 percent / imidazole / dimethylformamide / 13 h / 60 °C 8: 89 percent / pyridine / 0.5 h / Ambient temperature 9: 90 percent / tetra-n-butylammonium fluoride / tetrahydrofuran / 0.5 h / Ambient temperature 10: 47 percent / 1,1,3,3-tetramethylurea, stannous triflate, 4A molecular sieves / CH2Cl2 / 16 h / Ambient temperature 11: 95 percent / sodium methoxide / methanol / 1 h / Ambient temperature View Scheme

1: 99.4 percent / triethylamine / CH2Cl2 / 1.5 h / Ambient temperature 2: 57 percent / sodium azide / dimethylformamide / 3 h / 90 °C 3: 99.5 percent / triphenylphosphine / tetrahydrofuran; H2O / Ambient temperature 4: 95 percent / pyridine / Ambient temperature 5: 72 percent / hydrochloric acid / tetrahydrofuran / 1 h / Heating 6: 66 percent / imidazole / dimethylformamide / 13 h / 60 °C 7: 89 percent / pyridine / 0.5 h / Ambient temperature 8: 90 percent / tetra-n-butylammonium fluoride / tetrahydrofuran / 0.5 h / Ambient temperature 9: 47 percent / 1,1,3,3-tetramethylurea, stannous triflate, 4A molecular sieves / CH2Cl2 / 16 h / Ambient temperature 10: 95 percent / sodium methoxide / methanol / 1 h / Ambient temperature View Scheme

1: 1.) thionyl chloride; 2.) pyridine / 1.) 50 deg C 30 min; 2.) benzene, pyridine, ether, 1 h, r.t. 2: 95 percent / pyridine / Ambient temperature 3: 72 percent / hydrochloric acid / tetrahydrofuran / 1 h / Heating 4: 66 percent / imidazole / dimethylformamide / 13 h / 60 °C 5: 89 percent / pyridine / 0.5 h / Ambient temperature 6: 90 percent / tetra-n-butylammonium fluoride / tetrahydrofuran / 0.5 h / Ambient temperature 7: 47 percent / 1,1,3,3-tetramethylurea, stannous triflate, 4A molecular sieves / CH2Cl2 / 16 h / Ambient temperature 8: 95 percent / sodium methoxide / methanol / 1 h / Ambient temperature View Scheme

1: piperidine / dimethylformamide / 1 h 2: 28 mg / Et3N; DMAP / CH2Cl2 / 3 h / 20 °C 3: CF3CO2H / CH2Cl2; H2O / 12 h 4: 10.3 mg / NaOMe / methanol / 12 h View Scheme

1: CF3CO2H / CH2Cl2; H2O / 12 h 2: 10.3 mg / NaOMe / methanol / 12 h View Scheme

1: triphenylphosphine / tetrahydrofuran; H2O / 45 °C 2: 232 mg / triethylamine; 1-hydroxybenzotriazole; 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride / CH2Cl2 / 10 h / 20 °C 3: 85 percent / sodium methoxide / methanol; CH2Cl2 / 12 h / 20 °C / pH 9 View Scheme

1: 98.4 percent / BF3*OEt2; molecular sieves 4 Angstroem / CH2Cl2 / -20 °C 2: triphenylphosphine / tetrahydrofuran; H2O / 45 °C 3: 232 mg / triethylamine; 1-hydroxybenzotriazole; 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride / CH2Cl2 / 10 h / 20 °C 4: 85 percent / sodium methoxide / methanol; CH2Cl2 / 12 h / 20 °C / pH 9 View Scheme

1: 98.4 percent / BF3*OEt2; molecular sieves 4 Angstroem / CH2Cl2 / -20 °C 2: triphenylphosphine / tetrahydrofuran; H2O / 45 °C 3: 232 mg / triethylamine; 1-hydroxybenzotriazole; 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride / CH2Cl2 / 10 h / 20 °C 4: 85 percent / sodium methoxide / methanol; CH2Cl2 / 12 h / 20 °C / pH 9 View Scheme