Ethyl (2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxylate

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 3-picoline (52.6 ml, 543 mmol, 4 eq) was added to a slurry of ethyl (2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate (1:1) (50 g, 136 mmol, 1 eq) in dichloromethane (1000 ml) at 0° C., followed by a solution of triphosgene (36.4 g, 122.4 mmol, 0.9 eq) in dichloromethane (200 ml). The mixture was stirred at 0° C. until the reaction was deemed to be complete. The reaction was quenched with a solution of sodium bicarbonate (28.6 g, 340 mmol, 2.5 eq) in water (300 ml), and the layers were separated. The aqueous layer was extracted with dichloromethane (100 ml) and the combined organic layers were washed with water. The organic layer was concentrated in vacuo to give (2S,5R)-6-benzyloxy-7-oxo-1,6-diaza-bicyclo[3.2.1]octane-2-carboxylic acid ethyl ester as a solution in dichloromethane (solution yield: 35 g, 116 mmol, 85%). Acetonitrile was added and the solution was concentrated in vacuo to give (2S,5R)-6-benzyloxy-7-oxo-1,6-diaza-bicyclo[3.2.1]octane-2-carboxylic acid ethyl ester as a solution in acetonitrile. This solution was diluted with acetonitrile to 700 ml. To this was added ammonium carbamate (11.3 g, 145 mmol, 1.25 eq) and Novozyme 435 (35 g, immobilized Candida antarctica lipase B). The mixture was stirred at 40° C. until the reaction was deemed to be complete. The reaction mixture was filtered and concentrated in vacuo. The solution was diluted with dichloromethane, washed with aqueous ammonium chloride, and concentrated in vacuo. Chlorobutane was added and the solution was concentrated in vacuo. The precipitate was isolated by filtration, washed with chlorobutane and dried to give 2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamide as a white solid (24.3 g, 88 mmol, 65% from ethyl (2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate). the layers were separated The aqueous layer was extracted with dichloromethane (100 ml) the combined organic layers were washed with water The organic layer was concentrated in vacuo

Conditions: temp:-5.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: LiBH4 (0.54 g, 24.67 mmol) was added to a solution of (2S,5R)-ethyl 6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxylate (5 g, 16.44 mmol) in MeOH (50 mL) at −10° C. After 15 min, another portion of LiBH4 (0.54 g, 24.67 mmol) was added and the mixture was stirred at −10 to 0° C. for 4-5 h. The reaction mixture was carefully quenched by addition of sat. NaH2PO4 (50 mL) at 0° C. The mixture was diluted with water (20 mL) and extracted with DCM three times. The combined organic layer was concentrated and purified by silica gel column chromatography (gradient elution 0-100% petroleum ether/EtOAc, then 0-2% MeOH/EtOAc) to give (2S,5R)-6-(benzyloxy)-2-(hydroxymethyl)-1,6-diazabicyclo[3.2.1]octan-7-one (3.8 g, 88%) as a white solid. ESI-MS (EI+, m/z): 263.1. 1H-NMR (500M, CDCl3): 7.44-7.35 (m, 5H), 5.05 (d, J=11.5 Hz, 1H), 4.90 (d, J=11.5 Hz, 1H), 3.73-3.69 (m, 1H), 3.61-3.58 (m, 2H), 3.33 (m, 1H), 3.01 (br d, J=12.0 Hz, 1H), 2.91 (m, 1H), 2.03-1.95 (m, 2H), 1.58-1.54 (m, 1H), 1.39-1.24 (m, 1H). The reaction mixture was carefully quenched by addition of sat. NaH2PO4 (50 mL) at 0° C The mixture was diluted with water (20 mL) extracted with DCM three times The combined organic layer was concentrated purified by silica gel column chromatography ( gradient elution 0-100% petroleum ether/EtOAc

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

Procedure: LiOH (1.2 g, 29.6 mmol) was added to a solution of (2S,5R)-ethyl 6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxylate (9 g, 29.6 mmol) in THF/H2O (3:1, 240 mL). The mixture was then stirred at it overnight. The reaction mixture was washed with EtOAc twice, then the aqueous solution was adjusted pH 2-3 with 1N HCl. The resulting mixture was extracted with DCM three times, and the combined organic layer was dried over saturated Na2SO4 and concentrated in vacuum to provide (2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxylic acid (7.0 g, 77.7%), which was directly used in the next step without further purification. ESI-MS (EI+, m/z): 277.31. 1H NMR (300 MHz, CDCl3) δ 7.49-7.29 (m, 5H), 5.06 (d, J=11.4 Hz, 1H), 4.91 (d, J=11.4 Hz, 1H), 4.15-4.10 (m, 1H), 3.36-3.34 (m, 1H), 3.15-3.11 (m, 1H), 2.83 (d, J=11.8 Hz, 1H), 2.32-2.15 (m, 1H), 2.11-2.01 (m, 2H), 1.74-1.56 (m, 1H). The reaction mixture was washed with EtOAc twice The resulting mixture was extracted with DCM three times the combined organic layer was dried over saturated Na2SO4 concentrated in vacuum

Conditions: temp:20.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Triphosgene (21.3 g, 72 mmol) was added in portions to a solution of (2S,5R)-ethyl 5-((benzyloxy)amino)piperidine-2-carboxylate (50 g, 0.18 mol) and DIPEA (128 mL, 0.72 mol) in DCM (2000 mL) at 0° C. After stirring at 20° C. overnight, the reaction mixture was washed with H3PO4 (10%), sat. NaHCO3 and saturated NaCl. The combined organic layer was concentrated in vacuum and purified by silica gel column chromatography (3:1 petroleum ether/EtOAc) to afford (2S,5R)-ethyl 6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxylate (27.4 g, 50%) as a yellow solid. 1H NMR (400 Mz, CDCl3): δ 7.43-7.36 (m, 5H), 5.06 (d, J=11.4 Hz, 1H), 4.90 (d, J=11.4 Hz, 1H), 4.24 (q, J=7.1 Hz, 2H), 4.11-4.08 (m, 1H), 3.32-3.31 (m, 1H), 3.08-3.05 (m, 1H), 2.93 (d, J=11.9 Hz, 1H), 2.14-2.05 (m, 2H), 2.05-2.00 (m, 1H), 1.71-1.63 (m, 1H), 1.29 (t, J=7.1 Hz, 3H). the reaction mixture was washed with H3PO4 (10%), sat. NaHCO3 and saturated NaCl The combined organic layer was concentrated in vacuum purified by silica gel column chromatography (3:1 petroleum ether/EtOAc)

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 3-picoline (52.6 ml, 543 mmol, 4 eq) was added to a slurry of ethyl (2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate (1:1) (50 g, 136 mmol, 1 eq) in dichloromethane (1000 ml) at 0° C., followed by a solution of triphosgene (36.4 g, 122.4 mmol, 0.9 eq) in dichloromethane (200 ml). The mixture was stirred at 0° C. until the reaction was deemed to be complete. The reaction was quenched with a solution of sodium bicarbonate (28.6 g, 340 mmol, 2.5 eq) in water (300 ml), and the layers were separated. The aqueous layer was extracted with dichloromethane (100 ml) and the combined organic layers were washed with water. The organic layer was concentrated in vacuo to give (2S,5R)-6-benzyloxy-7-oxo-1,6-diaza-bicyclo[3.2.1]octane-2-carboxylic acid ethyl ester as a solution in dichloromethane (solution yield: 35 g, 116 mmol, 85%). Acetonitrile was added and the solution was concentrated in vacuo to give (2S,5R)-6-benzyloxy-7-oxo-1,6-diaza-bicyclo[3.2.1]octane-2-carboxylic acid ethyl ester as a solution in acetonitrile. This solution was diluted with acetonitrile to 700 ml. To this was added ammonium carbamate (11.3 g, 145 mmol, 1.25 eq) and Novozyme 435 (35 g, immobilized Candida antarctica lipase B). The mixture was stirred at 40° C. until the reaction was deemed to be complete. The reaction mixture was filtered and concentrated in vacuo. The solution was diluted with dichloromethane, washed with aqueous ammonium chloride, and concentrated in vacuo. Chlorobutane was added and the solution was concentrated in vacuo. The precipitate was isolated by filtration, washed with chlorobutane and dried to give 2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamide as a white solid (24.3 g, 88 mmol, 65% from ethyl (2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate). the layers were separated The aqueous layer was extracted with dichloromethane (100 ml) the combined organic layers were washed with water The organic layer was concentrated in vacuo

Conditions: temp:-5.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: LiBH4 (0.54 g, 24.67 mmol) was added to a solution of (2S,5R)-ethyl 6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxylate (5 g, 16.44 mmol) in MeOH (50 mL) at −10° C. After 15 min, another portion of LiBH4 (0.54 g, 24.67 mmol) was added and the mixture was stirred at −10 to 0° C. for 4-5 h. The reaction mixture was carefully quenched by addition of sat. NaH2PO4 (50 mL) at 0° C. The mixture was diluted with water (20 mL) and extracted with DCM three times. The combined organic layer was concentrated and purified by silica gel column chromatography (gradient elution 0-100% petroleum ether/EtOAc, then 0-2% MeOHEtOAc) to give (2S,5R)-6-(benzyloxy)-2-(hydroxymethyl)-1,6-diazabicyclo[3.2.1]octan-7-one (3.8 g, 88%) as a white solid. ESI-MS (EI+, m/z): 263.1. 1H-NMR (500M, CDCl3): 7.44-7.35 (m, 5H), 5.05 (d, J=11.5 Hz, 1H), 4.90 (d, J=11.5 Hz, 1H), 3.73-3.69 (m, 1H), 3.61-3.58 (m, 2H), 3.33 (m, 1H), 3.01 (br d, J=12.0 Hz, 1H), 2.91 (m, 1H), 2.03-1.95 (m, 2H), 1.58-1.54 (m, 1H), 1.39-1.24 (m, 1H). The reaction mixture was carefully quenched by addition of sat. NaH2PO4 (50 mL) at 0° C The mixture was diluted with water (20 mL) extracted with DCM three times The combined organic layer was concentrated purified by silica gel column chromatography ( gradient elution 0-100% petroleum ether/EtOAc

Conditions: temp:-5.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: LiBH4 (0.54 g, 24.67 mmol) was added to a solution of (2S,5R)-ethyl 6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxylate (5 g, 16.44 mmol) in MeOH (50 mL) at −10° C. After 15 min, another portion of LiBH4 (0.54 g, 24.67 mmol) was added and the mixture was stirred at −10 to 0° C. for 4-5 h. The reaction mixture was carefully quenched by addition of sat. NaH2PO4 (50 mL) at 0° C. The mixture was diluted with water (20 mL) and extracted with DCM three times. The combined organic layer was concentrated and purified by silica gel column chromatography (gradient elution 0-100% petroleum ether/EtOAc, then 0-2% MeOHEtOAc) to give (2S,5R)-6-(benzyloxy)-2-(hydroxymethyl)-1,6-diazabicyclo[3.2.1]octan-7-one (3.8 g, 88%) as a white solid. ESI-MS (EI+, m/z): 263.1. 1H-NMR (500M, CDCl3): 7.44-7.35 (m, 5H), 5.05 (d, J=11.5 Hz, 1H), 4.90 (d, J=11.5 Hz, 1H), 3.73-3.69 (m, 1H), 3.61-3.58 (m, 2H), 3.33 (m, 1H), 3.01 (br d, J=12.0 Hz, 1H), 2.91 (m, 1H), 2.03-1.95 (m, 2H), 1.58-1.54 (m, 1H), 1.39-1.24 (m, 1H). The reaction mixture was carefully quenched by addition of sat. NaH2PO4 (50 mL) at 0° C The mixture was diluted with water (20 mL) extracted with DCM three times The combined organic layer was concentrated purified by silica gel column chromatography ( gradient elution 0-100% petroleum ether/EtOAc

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

Procedure: LiOH (1.2 g, 29.6 mmol) was added to a solution of (2S,5R)-ethyl 6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxylate (9 g, 29.6 mmol) in THF/H2O (3:1, 240 mL). The mixture was then stirred at rt overnight. The reaction mixture was washed with EtOAc twice, then the aqueous solution was adjusted pH 2-3 with 1N HCl. The resulting mixture was extracted with DCM three times, and the combined organic layer was dried over saturated Na2SO4 and concentrated in vacuum to provide (2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxylic acid (7.0 g, 77.7%), which was directly used in the next step without further purification. ESI-MS (EI+, m/z): 277.31. 1H NMR (300 MHz, CDCl3) δ 7.49-7.29 (m, 5H), 5.06 (d, J=11.4 Hz, 1H), 4.91 (d, J=11.4 Hz, 1H), 4.15-4.10 (m, 1H), 3.36-3.34 (m, 1H), 3.15-3.11 (m, 1H), 2.83 (d, J=11.8 Hz, 1H), 2.32-2.15 (m, 1H), 2.11-2.01 (m, 2H), 1.74-1.56 (m, 1H). The reaction mixture was washed with EtOAc twice The resulting mixture was extracted with DCM three times the combined organic layer was dried over saturated Na2SO4 concentrated in vacuum

Conditions: temp:20.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Triphosgene (21.3 g, 72 mmol) was added in portions to a solution of (2S,5R)-ethyl 5-((benzyloxy)amino)piperidine-2-carboxylate (50 g, 0.18 mol) and DIPEA (128 mL, 0.72 mol) in DCM (2000 mL) at 0° C. After stirring at 20° C. overnight, the reaction mixture was washed with H3PO4 (10%), sat. NaHCO3 and saturated NaCl. The combined organic layer was concentrated in vacuum and purified by silica gel column chromatography (3:1 petroleum ether/EtOAc) to afford (2S,5R)-ethyl 6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxylate (27.4 g, 50%) as a yellow solid. 1H NMR (400 Mz, CDCl3): δ 7.43-7.36 (m, 5H), 5.06 (d, J=11.4 Hz, 1H), 4.90 (d, J=11.4 Hz, 1H), 4.24 (q, J=7.1 Hz, 2H), 4.11-4.08 (m, 1H), 3.32-3.31 (m, 1H), 3.08-3.05 (m, 1H), 2.93 (d, J=11.9 Hz, 1H), 2.14-2.05 (m, 2H), 2.05-2.00 (m, 1H), 1.71-1.63 (m, 1H), 1.29 (t, J=7.1 Hz, 3H). the reaction mixture was washed with H3PO4 (10%), sat. NaHCO3 and saturated NaCl The combined organic layer was concentrated in vacuum purified by silica gel column chromatography (3:1 petroleum ether/EtOAc)

Conditions: temp:20.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Triphosgene (21.3 g, 72 mmol) was added in portions to a solution of (2S,5R)-ethyl 5-((benzyloxy)amino)piperidine-2-carboxylate (50 g, 0.18 mol) and DIPEA (128 mL, 0.72 mol) in DCM (2000 mL) at 0° C. After stirring at 20° C. overnight, the reaction mixture was washed with H3PO4 (10%), sat. NaHCO3 and saturated NaCl. The combined organic layer was concentrated in vacuum and purified by silica gel column chromatography (3:1 petroleum ether/EtOAc) to afford (2S,5R)-ethyl 6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxylate (27.4 g, 50%) as a yellow solid. 1H NMR (400 Mz, CDCl3): δ 7.43-7.36 (m, 5H), 5.06 (d, J=11.4 Hz, 1H), 4.90 (d, J=11.4 Hz, 1H), 4.24 (q, J=7.1 Hz, 2H), 4.11-4.08 (m, 1H), 3.32-3.31 (m, 1H), 3.08-3.05 (m, 1H), 2.93 (d, J=11.9 Hz, 1H), 2.14-2.05 (m, 2H), 2.05-2.00 (m, 1H), 1.71-1.63 (m, 1H), 1.29 (t, J=7.1 Hz, 3H). the reaction mixture was washed with H3PO4 (10%), sat. NaHCO3 and saturated NaCl The combined organic layer was concentrated in vacuum purified by silica gel column chromatography (3:1 petroleum ether/EtOAc)

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

Procedure: LiOH (1.2 g, 29.6 mmol) was added to a solution of (2S,5R)-ethyl 6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxylate (9 g, 29.6 mmol) in THF/H2O (3:1, 240 mL). The mixture was then stirred at rt overnight. The reaction mixture was washed with EtOAc twice, then the aqueous solution was adjusted pH 2-3 with 1N HCl. The resulting mixture was extracted with DCM three times, and the combined organic layer was dried over saturated Na2SO4 and concentrated under reduced pressure to provide (2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxylic acid (7.0 g, 77.7%), which was directly used in the next step without further purification. ESI-MS (EI+, m/z): 277.31. 1H NMR (300 MHz, CDCl3) δ 7.49-7.29 (m, 5H), 5.06 (d, J=11.4 Hz, 1H), 4.91 (d, J=11.4 Hz, 1H), 4.15-4.10 (m, 1H), 3.36-3.34 (m, 1H), 3.15-3.11 (m, 1H), 2.83 (d, J=11.8 Hz, 1H), 2.32-2.15 (m, 1H), 2.11-2.01 (m, 2H), 1.74-1.56 (m, 1H). The reaction mixture was washed with EtOAc twice The resulting mixture was extracted with DCM three times the combined organic layer was dried over saturated Na2SO4 concentrated under reduced pressure

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

Procedure: LiOH (1.2 g, 29.6 mmol) was added to a solution of (2S,5R)-ethyl 6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxylate (9 g, 29.6 mmol) in THF/H2O (3:1, 240 mL). The mixture was then stirred at rt overnight. The reaction mixture was washed with EtOAc twice, then the aqueous solution was adjusted pH 2-3 with 1N HCl. The resulting mixture was extracted with DCM three times, and the combined organic layer was dried over saturated Na2SO4 and concentrated under reduced pressure to provide (2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxylic acid (7.0 g, 77.7%), which was directly used in the next step without further purification. ESI-MS (EI+, m/z): 277.31. 1H NMR (300 MHz, CDCl3) δ 7.49-7.29 (m, 5H), 5.06 (d, J=11.4 Hz, 1H), 4.91 (d, J=11.4 Hz, 1H), 4.15-4.10 (m, 1H), 3.36-3.34 (m, 1H), 3.15-3.11 (m, 1H), 2.83 (d, J=11.8 Hz, 1H), 2.32-2.15 (m, 1H), 2.11-2.01 (m, 2H), 1.74-1.56 (m, 1H). The reaction mixture was washed with EtOAc twice The resulting mixture was extracted with DCM three times the combined organic layer was dried over saturated Na2SO4 concentrated under reduced pressure