(3S)-3-azido-4,4-dimethyloxolan-2-one

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of (S)-3-azido-4,4-dimethyldihydrofuran-2(3H)-one (5.52 g) in MeOH 910 mL) was added 10% Pd/C (0.379 g, 0.356 mmol) under N2. The reaction mixture was stirred under H2 at rt for 16 hrs. The reaction was filtered through diatomaceous earth (Celite®), washed with EtOAc and the filtrate was concentrated to yield a clear oil. To the above oil in DCM (10 mL) was added BOC2O (9.09 mL) and TEA (13.88 mL). The reaction mixture was stirred at rt for 16 hrs. The reaction mixture was diluted with EtOAc, washed with sat. NaHCO3, citric acid, water, sat. NaCl, dried over anhydrous Na2SO4, filtered and concentrated to yield an oil. The crude product was purified by silica gel chromatography (0-100% EtOAc in hexane) to yield (S)-tert-butyl 4,4-dimethyl-2-oxotetrahydrofuran-3-ylcarbamate (3.8 g) as a white solid. LC/MS (Cond. N-1): [M+Na]+ 252.06, RT=2.75 min. 1H NMR (400 MHz, CHLOROFORM-d) ppm 4.81-4.95 (1H, m), 4.38 (1H, d, J=7.78 Hz), 3.97-4.07 (2H, m), 1.47 (9H, s), 1.25 (3H, s), 1.01 (3H, s). The reaction was filtered through diatomaceous earth (Celite®) washed with EtOAc the filtrate was concentrated to yield a clear oil The reaction mixture was stirred at rt for 16 hrs washed with sat. NaHCO3, citric acid, water, sat. NaCl dried over anhydrous Na2SO4 filtered concentrated to yield an oil The crude product was purified by silica gel chromatography (0-100% EtOAc in hexane)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of (S)-3-azido-4,4-dimethyldihydrofuran-2(3H)-one (5.52 g) in MeOH 910 mL) was added 10% Pd/C (0.379 g, 0.356 mmol) under N2. The reaction mixture was stirred under H2 at rt for 16 hrs. The reaction was filtered through diatomaceous earth (Celite®), washed with EtOAc and the filtrate was concentrated to yield a clear oil. To the above oil in DCM (10 mL) was added BOC2O (9.09 mL) and TEA (13.88 mL). The reaction mixture was stirred at rt for 16 hrs. The reaction mixture was diluted with EtOAc, washed with sat. NaHCO3, citric acid, water, sat. NaCl, dried over anhydrous Na2SO4, filtered and concentrated to yield an oil. The crude product was purified by silica gel chromatography (0-100% EtOAc in hexane) to yield (S)-tert-butyl 4,4-dimethyl-2-oxotetrahydrofuran-3-ylcarbamate (3.8 g) as a white solid. LC/MS (Cond. N-1): [M+Na]+ 252.06, RT=2.75 min. 1H NMR (400 MHz, CHLOROFORM-d) ppm 4.81-4.95 (1H, m), 4.38 (1H, d, J=7.78 Hz), 3.97-4.07 (2H, m), 1.47 (9H, s), 1.25 (3H, s), 1.01 (3H, s). The reaction was filtered through diatomaceous earth (Celite®) washed with EtOAc the filtrate was concentrated to yield a clear oil The reaction mixture was stirred at rt for 16 hrs washed with sat. NaHCO3, citric acid, water, sat. NaCl dried over anhydrous Na2SO4 filtered concentrated to yield an oil The crude product was purified by silica gel chromatography (0-100% EtOAc in hexane)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of (R)-4,4-dimethyl-2-oxotetrahydrofuran-3-yl trifluoromethanesulfonate (10 g) in DCM (10 mL) was added tetra-n-butylammonium azide (11.1 g). The reaction mixture was stirred at rt for 16 hr. The reaction was diluted with EtOAc, washed with water, sat. NaHCO3, citric acid, water, and sat. NaCl, dried over anhydrous Na2SO4, filtered and concentrated to yield an oil. The crude product was purified by silica gel chromatography (0-100% EtOAc in hexane) to yield (S)-3-azido-4,4-dimethyldihydrofuran-2(3H)-one as a white solid. 1H NMR (400 MHz, CHLOROFORM-d) ppm 3.87-4.02 (3H, m), 1.17 (3H, s), 1.02 (3H, s). washed with water, sat. NaHCO3, citric acid, water, and sat. NaCl dried over anhydrous Na2SO4 filtered concentrated to yield an oil The crude product was purified by silica gel chromatography (0-100% EtOAc in hexane)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution containing the product from Example 174A (4.6 g, 17.56 mmol) in toluene (80.0 mL) was added tetra-n-butylammonium azide (5.0 g, 17.57 mmol) at room temperature, and the mixture was stirred for 5 hours. The reaction was diluted with ether and washed with water, dilute NaHCO3, 10% citric acid and brine. The organic layer was dried over MgSO4, filtered and concentrated to give the crude product, which was used without further purification (2.79 g). washed with water, dilute NaHCO3, 10% citric acid and brine The organic layer was dried over MgSO4 filtered concentrated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of (S)-3-azido-4,4-dimethyldihydrofuran-2(3H)-one (5.52 g) in MeOH 910 mL) was added 10% Pd/C (0.379 g, 0.356 mmol) under N2. The reaction mixture was stirred under H2 at rt for 16 hrs. The reaction was filtered through diatomaceous earth (Celite®), washed with EtOAc and the filtrate was concentrated to yield a clear oil. To the above oil in DCM (10 mL) was added BOC2O (9.09 mL) and TEA (13.88 mL). The reaction mixture was stirred at rt for 16 hrs. The reaction mixture was diluted with EtOAc, washed with sat. NaHCO3, citric acid, water, sat. NaCl, dried over anhydrous Na2SO4, filtered and concentrated to yield an oil. The crude product was purified by silica gel chromatography (0-100% EtOAc in hexane) to yield (S)-tert-butyl 4,4-dimethyl-2-oxotetrahydrofuran-3-ylcarbamate (3.8 g) as a white solid. LC/MS (Cond. N-1): [M+Na]+ 252.06, RT=2.75 min. 1H NMR (400 MHz, CHLOROFORM-d) ppm 4.81-4.95 (1H, m), 4.38 (1H, d, J=7.78 Hz), 3.97-4.07 (2H, m), 1.47 (9H, s), 1.25 (3H, s), 1.01 (3H, s). The reaction was filtered through diatomaceous earth (Celite®) washed with EtOAc the filtrate was concentrated to yield a clear oil The reaction mixture was stirred at rt for 16 hrs washed with sat. NaHCO3, citric acid, water, sat. NaCl dried over anhydrous Na2SO4 filtered concentrated to yield an oil The crude product was purified by silica gel chromatography (0-100% EtOAc in hexane)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of (R)-4,4-dimethyl-2-oxotetrahydrofuran-3-yl trifluoromethanesulfonate (10 g) in DCM (10 mL) was added tetra-n-butylammonium azide (11.1 g). The reaction mixture was stirred at rt for 16 hr. The reaction was diluted with EtOAc, washed with water, sat. NaHCO3, citric acid, water, and sat. NaCl, dried over anhydrous Na2SO4, filtered and concentrated to yield an oil. The crude product was purified by silica gel chromatography (0-100% EtOAc in hexane) to yield (S)-3-azido-4,4-dimethyldihydrofuran-2(3H)-one as a white solid. 1H NMR (400 MHz, CHLOROFORM-d) ppm 3.87-4.02 (3H, m), 1.17 (3H, s), 1.02 (3H, s). washed with water, sat. NaHCO3, citric acid, water, and sat. NaCl dried over anhydrous Na2SO4 filtered concentrated to yield an oil The crude product was purified by silica gel chromatography (0-100% EtOAc in hexane)