1: 1.) triethylamine, 2-mesitylenesulfonyl chloride, 4-N,N-dimethylaminopyridine, 2.) 1,4-diazabicyclo<2.2.2>octane, triethylamine / 1.) dichloromethane, 20 deg C, 1 h, 2.) dichloromethane, 20 deg C, 1 h 2: tetrabutylammonium fluoride / tetrahydrofuran / 0.08 h / 20 °C 3: 4-nitrobenzaldoxime, N,N,N',N'-tetramethylguanidine / dioxane; H2O / 0.05 h / 20 °C 4: pyridine / 1 h / 20 °C View Scheme

1: 1.) triethylamine, 2-mesitylenesulfonyl chloride, 4-N,N-dimethylaminopyridine, 2.) 1,4-diazabicyclo<2.2.2>octane, triethylamine / 1.) dichloromethane, 20 deg C, 1 h, 2.) dichloromethane, 20 deg C, 1 h 2: tetrabutylammonium fluoride / tetrahydrofuran / 0.08 h / 20 °C 3: 4-nitrobenzaldoxime, N,N,N',N'-tetramethylguanidine / dioxane; H2O / 0.05 h / 20 °C View Scheme

1: 1.) triethylamine, 2-mesitylenesulfonyl chloride, 4-N,N-dimethylaminopyridine, 2.) 1,4-diazabicyclo<2.2.2>octane, triethylamine / 1.) dichloromethane, 20 deg C, 1 h, 2.) dichloromethane, 20 deg C, 1 h 2: tetrabutylammonium fluoride / tetrahydrofuran / 0.08 h / 20 °C 3: ammonia / methanol / 5 h / 20 °C View Scheme

1: 1.) triethylamine, 2-mesitylenesulfonyl chloride, N,N-dimethylaminopyridine, 2.) 1,4-diazabicyclo<2.2.2>octane / 1.) dichloromethane, 30 min, 2.) dichloromethane, 60 min 2: 1.12 g / p-toluenesulfonic acid / CH2Cl2 / 0.03 h / 20 °C 3: 81 percent / silver oxide / acetone / 72 h / 20 °C 4: 70 percent / syn-4-nitrobenxaldoxime, N1,N1,N3,N3-tetramethylguanidine / dioxane; H2O / 16 h / 20 °C 5: 95 percent / tetrabutylammonium fluoride / tetrahydrofuran / 2 h / 20 °C View Scheme

1: 1.) triethylamine, 2-mesitylenesulfonyl chloride, N,N-dimethylaminopyridine, 2.) 1,4-diazabicyclo<2.2.2>octane / 1.) dichloromethane, 30 min, 2.) dichloromethane, 60 min 2: 1.12 g / p-toluenesulfonic acid / CH2Cl2 / 0.03 h / 20 °C 3: 81 percent / silver oxide / acetone / 72 h / 20 °C 4: 75 percent / ammonia / tetrahydrofuran 5: 96 percent / tetrabutylammonium fluoride / tetrahydrofuran / 20 °C View Scheme

1: 1.) triethylamine, 2-mesitylenesulfonyl chloride, 4-N,N-dimethylaminopyridine, 2.) 1,4-diazabicyclo<2.2.2>octane, triethylamine / 1.) dichloromethane, 20 deg C, 1 h, 2.) dichloromethane, 20 deg C, 1 h 2: tetrabutylammonium fluoride / tetrahydrofuran / 0.08 h / 20 °C 3: 4-nitrobenzaldoxime, N,N,N',N'-tetramethylguanidine / dioxane; H2O / 0.05 h / 20 °C 4: pyridine / 1 h / 20 °C 5: 1.) triethylamine, 2-mesitylenesulfonyl chloride, 4-N,N-dimethylaminopyridine, 2.) 1,4-diazabicyclo<2.2.2>octane, triethylamine / 1.) dichloromethane, 20 deg C, 1 h, 2.) dichloromethane, 20 deg C, 1 h 6: acetonitrile / 8 h / 20 °C 7: 1.) triethylamine, 2.) aq. ammonia / 1.) ethanol, 20 deg C, 10 min View Scheme

1: 1.) triethylamine, 2-mesitylenesulfonyl chloride, N,N-dimethylaminopyridine, 2.) 1,4-diazabicyclo<2.2.2>octane / 1.) dichloromethane, 30 min, 2.) dichloromethane, 60 min 2: 1.12 g / p-toluenesulfonic acid / CH2Cl2 / 0.03 h / 20 °C 3: 81 percent / silver oxide / acetone / 72 h / 20 °C 4: 80 percent / triethylamine / ethanol / 72 h / 20 °C 5: 95 percent / tetrabutylammonium fluoride / tetrahydrofuran / 20 °C View Scheme