tert-butyl 3-(2-hydroxyethyl)azetidine-1-carboxylate

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

Procedure: A stirred solution of tert-butyl 3-(2-hydroxyethyl)azetidine-1-carboxylate (254 mg, 1.26 mmol), Ph3P (381 mg, 1.45 mmol.15), imidazole (129 mg, 1.89 mmol0) and acetonitrile (6.5 mL) at 0° C.; was treated with iodine (368 mg, 1.45 mmol.15). Mixture was allowed to reach 25° C. and stirring continued for 18 h. The reaction mixture was then diluted with water and extracted with hexanes (6×25 mL). The combined organics were dried (MgSO4) and concentrated, then purified by chromatography (40 g column, 50 μm from Analogix, 0-30% EtOAc in hexanes over 15 min to give tert-butyl 3-(2-iodoethyl)azetidine-1-carboxylate (271 mg, 871 μmol, 69.0%) as a colorless oil. 1H NMR (CDCl3) δ: 4.03 (t, J=8.3 Hz, 2H), 3.56 (dd, J=8.7, 5.7 Hz, 2H), 3.10 (t, J=7.0 Hz, 2H), 2.63 (quint, J=7.8, 5.4 Hz, 1H), 2.13 (q, J=7.1 Hz, 2H), 1.42 (s, 9H). at 0° C. to reach 25° C. extracted with hexanes (6×25 mL) The combined organics were dried (MgSO4) concentrated purified by chromatography (40 g column, 50 μm from Analogix, 0-30% EtOAc in hexanes over 15 min

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

Procedure: A stirred solution of tert-butyl 3-(2-hydroxyethyl)azetidine-1-carboxylate (254 mg, 1.26 mmol), Ph3P (381 mg, 1.45 mmol.15), imidazole (129 mg, 1.89 mmol0) and acetonitrile (6.5 mL) at 0° C.; was treated with iodine (368 mg, 1.45 mmol.15). Mixture was allowed to reach 25° C. and stirring continued for 18 h. The reaction mixture was then diluted with water and extracted with hexanes (6×25 mL). The combined organics were dried (MgSO4) and concentrated, then purified by chromatography (40 g column, 50 μm from Analogix, 0-30% EtOAc in hexanes over 15 min to give tert-butyl 3-(2-iodoethyl)azetidine-1-carboxylate (271 mg, 871 μmol, 69.0%) as a colorless oil. 1H NMR (CDCl3) δ: 4.03 (t, J=8.3 Hz, 2H), 3.56 (dd, J=8.7, 5.7 Hz, 2H), 3.10 (t, J=7.0 Hz, 2H), 2.63 (quint, J=7.8, 5.4 Hz, 1H), 2.13 (q, J=7.1 Hz, 2H), 1.42 (s, 9H). at 0° C. to reach 25° C. extracted with hexanes (6×25 mL) The combined organics were dried (MgSO4) concentrated purified by chromatography (40 g column, 50 μm from Analogix, 0-30% EtOAc in hexanes over 15 min

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

Procedure: A solution of 2-(1-(tert-butoxycarbonyl)azetidin-3-yl)acetic acid (529 mg, 2.46 mmol) in THF (5.29 mL) was cooled to 0° C. and treated with a borane-methyl sulfide complex 2M in THF (2.46 mL, 4.92 mmol), then slowly warmed to rt. After stirring for 18 h, the reaction mixture was quenched by drop-wise addition of 2 N NaOH (7 mL) then extracted with dichloromethane (4×30 mL). The organic layers were combined, dried (MgSO4), and concentrated to give tert-butyl 3-(2-hydroxyethyl)azetidine-1-carboxylate (495 mg, 2.46 mmol, 100%) as a colorless oil. 1H NMR (CDCl3) δ: 3.96 (t, J=8.3 Hz, 2H), 3.47-3.64 (m, 4H), 2.50-2.67 (m, 1H), 1.73-1.86 (m, 2H), 1.37 (s, 9H). the reaction mixture was quenched by drop-wise addition of 2 N NaOH (7 mL) then extracted with dichloromethane (4×30 mL) dried (MgSO4) concentrated

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

Procedure: A solution of 2-(1-(tert-butoxycarbonyl)azetidin-3-yl)acetic acid (529 mg, 2.46 mmol) in THF (5.29 mL) was cooled to 0° C. and treated with a borane-methyl sulfide complex 2M in THF (2.46 mL, 4.92 mmol), then slowly warmed to rt. After stirring for 18 h, the reaction mixture was quenched by drop-wise addition of 2 N NaOH (7 mL) then extracted with dichloromethane (4×30 mL). The organic layers were combined, dried (MgSO4), and concentrated to give tert-butyl 3-(2-hydroxyethyl)azetidine-1-carboxylate (495 mg, 2.46 mmol, 100%) as a colorless oil. 1H NMR (CDCl3) δ: 3.96 (t, J=8.3 Hz, 2H), 3.47-3.64 (m, 4H), 2.50-2.67 (m, 1H), 1.73-1.86 (m, 2H), 1.37 (s, 9H). the reaction mixture was quenched by drop-wise addition of 2 N NaOH (7 mL) then extracted with dichloromethane (4×30 mL) dried (MgSO4) concentrated

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

Procedure: To a solution of oxalyl chloride (488 μl, 5.58 mmol) in 40 ml dichloromethane at −78° C. was added dimethyl sulfoxide (792 μl, 11.16 mmol) dropwise by syringe. The mixture was stirred for 15 minutes at −78° C. when a solution of tert-butyl 3-(2-hydroxyethyl)azetidine-1-carboxylate (936 mg, 4.65 mmol) in 10 ml dichloromethane was added dropwise by syringe. After 1 hour at −78° C., triethylamine (3241 μl, 23.25 mmol) was added and the suspension was warmed to room temperature and stirred for an additional hour. The mixture was quenched with water (25 ml) and saturated aqueous potassium carbonate (10 ml), stirred vigorously and separated. The aqueous layer was extracted with dichloromethane (2×20 ml) and the combined organic layers were dried with magnesium sulfate, filtered and concentrated. The crude material was flash chromatographed to give the title compound. was added dropwise by syringe The mixture was quenched with water (25 ml) and saturated aqueous potassium carbonate (10 ml) stirred vigorously separated The aqueous layer was extracted with dichloromethane (2×20 ml) the combined organic layers were dried with magnesium sulfate filtered concentrated chromatographed

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

Procedure: To a solution of oxalyl chloride (488 μl, 5.58 mmol) in 40 ml dichloromethane at −78° C. was added dimethyl sulfoxide (792 μl, 11.16 mmol) dropwise by syringe. The mixture was stirred for 15 minutes at −78° C. when a solution of tert-butyl 3-(2-hydroxyethyl)azetidine-1-carboxylate (936 mg, 4.65 mmol) in 10 ml dichloromethane was added dropwise by syringe. After 1 hour at −78° C., triethylamine (3241 μl, 23.25 mmol) was added and the suspension was warmed to room temperature and stirred for an additional hour. The mixture was quenched with water (25 ml) and saturated aqueous potassium carbonate (10 ml), stirred vigorously and separated. The aqueous layer was extracted with dichloromethane (2×20 ml) and the combined organic layers were dried with magnesium sulfate, filtered and concentrated. The crude material was flash chromatographed to give the title compound. was added dropwise by syringe The mixture was quenched with water (25 ml) and saturated aqueous potassium carbonate (10 ml) stirred vigorously separated The aqueous layer was extracted with dichloromethane (2×20 ml) the combined organic layers were dried with magnesium sulfate filtered concentrated chromatographed

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

Procedure: A solution of 2-(1-(tert-butoxycarbonyl)azetidin-3-yl)acetic acid (1 g, 4.65 mmol) in tetrahydrofuran (5 ml) was cooled to 0° C. and treated with borane tetrahydrofuran complex (7.00 ml, 7 mmol) dropwise by syringe. After 1 hour at 0° C. the solution was allowed to warm to room temperature and stirred overnight and then it was quenched with 20 ml of 1M aqueous NaOH. The separated aqueous layer was extracted with ether (2×15 ml), dried with magnesium sulfate, filtered and concentrated to give the title compound which was used without purification. treated with borane tetrahydrofuran complex (7.00 ml, 7 mmol) dropwise by syringe it was quenched with 20 ml of 1M aqueous NaOH The separated aqueous layer was extracted with ether (2×15 ml) dried with magnesium sulfate filtered concentrated

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

Procedure: 4-Bromo-2-(trifluoromethyl)phenol (3 g), tert-butyl 3-(2-hydroxyethyl)azetidine-1-carboxylate (2.81 g) and triphenylphosphine (3.92 g) were dissolved in DCM (25 ml). The reaction mixture was placed under a nitrogen atmosphere and cooled to 0° C. then DIAD (2.94 ml) was added dropwise. The mixture was stirred at room temperature for 16 hours then solvent evaporated under reduced pressure. The resulting residue was dissolved in ether (10 ml), heptane (15 mL) was then added and the suspension stirred for 45 minutes. The mixture was filtered (solid was washed with 3:2 heptane/ether) and the filtrate washed with NaOH (1M, 2×40 mL). Organics were dried over sodium sulphate and solvent evaporated under reduced pressure to yield crude product as a clear oil (6.05 g). Purification by flash chromatography (100 g silica column, 10% to 25% EtOAc in heptane gradient) afforded tert-butyl 3-(2-(4-bromo-2-(trifluoromethyl)phenoxy)ethyl)azetidine-1-carboxylate (52.6% yield) as a clear oil. solvent evaporated under reduced pressure The resulting residue was dissolved in ether (10 ml) heptane (15 mL) was then added the suspension stirred for 45 minutes The mixture was filtered (solid was washed with 3:2 heptane/ether) the filtrate washed with NaOH (1M, 2×40 mL) Organics were dried over sodium sulphate and solvent evaporated under reduced pressure to yield crude product as a clear oil (6.05 g) Purification by flash chromatography (100 g silica column, 10% to 25% EtOAc in heptane gradient)

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

Procedure: 4-Bromo-2-(trifluoromethyl)phenol (3 g), tert-butyl 3-(2-hydroxyethyl)azetidine-1-carboxylate (2.81 g) and triphenylphosphine (3.92 g) were dissolved in DCM (25 ml). The reaction mixture was placed under a nitrogen atmosphere and cooled to 0° C. then DIAD (2.94 ml) was added dropwise. The mixture was stirred at room temperature for 16 hours then solvent evaporated under reduced pressure. The resulting residue was dissolved in ether (10 ml), heptane (15 mL) was then added and the suspension stirred for 45 minutes. The mixture was filtered (solid was washed with 3:2 heptane/ether) and the filtrate washed with NaOH (1M, 2×40 mL). Organics were dried over sodium sulphate and solvent evaporated under reduced pressure to yield crude product as a clear oil (6.05 g). Purification by flash chromatography (100 g silica column, 10% to 25% EtOAc in heptane gradient) afforded tert-butyl 3-(2-(4-bromo-2-(trifluoromethyl)phenoxy)ethyl)azetidine-1-carboxylate (52.6% yield) as a clear oil. solvent evaporated under reduced pressure The resulting residue was dissolved in ether (10 ml) heptane (15 mL) was then added the suspension stirred for 45 minutes The mixture was filtered (solid was washed with 3:2 heptane/ether) the filtrate washed with NaOH (1M, 2×40 mL) Organics were dried over sodium sulphate and solvent evaporated under reduced pressure to yield crude product as a clear oil (6.05 g) Purification by flash chromatography (100 g silica column, 10% to 25% EtOAc in heptane gradient)

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

Procedure: 2-(1-(tert-Butoxycarbonyl)azetidin-3-yl)acetic acid (3.91 g) was dissolved in THF (18.17 ml) and cooled to 0° C. Diborane (1M in THF, 54.5 ml) was added dropwise and the reaction stirred for one hour. Water was added dropwise to quench unreacted borane and the mixture diluted with EtOAc (150 mL) and washed with water (100 mL). Organics were dried over sodium sulphate and solvent evaporated under reduced pressure to afford tert-butyl 3-(2-hydroxyethyl)azetidine-1-carboxylate (100% yield) as a clear oil. to quench unreacted borane the mixture diluted with EtOAc (150 mL) washed with water (100 mL) Organics were dried over sodium sulphate and solvent evaporated under reduced pressure

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

Procedure: A stirred solution of tert-butyl 3-(2-hydroxyethyl)azetidine-1-carboxylate (254 mg, 1.26 mmol), Ph3P (381 mg, 1.45 mmol.15), imidazole (129 mg, 1.89 mmol0) and acetonitrile (6.5 mL) at 0° C.; was treated with iodine (368 mg, 1.45 mmol.15). Mixture was allowed to reach 25° C. and stirring continued for 18 h. The reaction mixture was then diluted with water and extracted with hexanes (6×25 mL). The combined organics were dried (MgSO4) and concentrated, then purified by chromatography (40 g column, 50 μm from Analogix, 0-30% EtOAc in hexanes over 15 min to give tert-butyl 3-(2-iodoethyl)azetidine-1-carboxylate (271 mg, 871 μmol, 69.0%) as a colorless oil. 1H NMR (CDCl3) δ: 4.03 (t, J=8.3 Hz, 2H), 3.56 (dd, J=8.7, 5.7 Hz, 2H), 3.10 (t, J=7.0 Hz, 2H), 2.63 (quint, J=7.8, 5.4 Hz, 1H), 2.13 (q, J=7.1 Hz, 2H), 1.42 (s, 9H). at 0° C. to reach 25° C. extracted with hexanes (6×25 mL) The combined organics were dried (MgSO4) concentrated purified by chromatography (40 g column, 50 μm from Analogix, 0-30% EtOAc in hexanes over 15 min

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

Procedure: A solution of 2-(1-(tert-butoxycarbonyl)azetidin-3-yl)acetic acid (529 mg, 2.46 mmol) in THF (5.29 mL) was cooled to 0° C. and treated with a borane-methyl sulfide complex 2M in THF (2.46 mL, 4.92 mmol), then slowly warmed to rt. After stirring for 18 h, the reaction mixture was quenched by drop-wise addition of 2 N NaOH (7 mL) then extracted with dichloromethane (4×30 mL). The organic layers were combined, dried (MgSO4), and concentrated to give tert-butyl 3-(2-hydroxyethyl)azetidine-1-carboxylate (495 mg, 2.46 mmol, 100%) as a colorless oil. 1H NMR (CDCl3) δ: 3.96 (t, J=8.3 Hz, 2H), 3.47-3.64 (m, 4H), 2.50-2.67 (m, 1H), 1.73-1.86 (m, 2H), 1.37 (s, 9H). the reaction mixture was quenched by drop-wise addition of 2 N NaOH (7 mL) then extracted with dichloromethane (4×30 mL) dried (MgSO4) concentrated