tert-butyl 2-oxoazetidine-1-carboxylate

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

Procedure: To a solution of compound 4d (TFA salt, 124 mg, 0.39 mmol) and compound 1e (94 mg, 0.55 mmol) in 1,2-DCE (2 mL) was added acetic acid (0.1 mL). To this mixture was added Na(OAc)3BH (132 mg, 0.624 mmol). The reaction was stirred at room temperature for 4 h. To the reaction mixture was added aq. NaHCO3, and the resultant mixture was extracted with CH2Cl2. The organic layer was dried over Na2SO4 and concentrated. Purification by flash column chromatography (silica gel, 5% MeOH/EtOAc+0.5% TEA) gave compound 4e (0.11 g). MS m/z (M+H+) 360.5. the resultant mixture was extracted with CH2Cl2 The organic layer was dried over Na2SO4 concentrated Purification by flash column chromatography (silica gel, 5% MeOH/EtOAc+0.5% TEA)

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

Procedure: To a solution of compound 1d (diHCl salt, 2.7 g, 10 mmol) and N-Boc azetidinone 1e (2.4 g, 14 mmol) in 1,2-DCE (50 mL) was added slowly Et3N (20 mmol) followed by acetic acid (3.5 mL). To this mixture was added Na(OAc)3BH (3.39 g, 16 mmol). The reaction was stirred at room temperature for 5 h. To the reaction mixture was added aq. NaHCO3, and the resultant mixture was extracted with CH2Cl2. The organic layer was dried over Na2SO4 and concentrated. Purification by flash column chromatography (silica gel, 80% EtOAc/heptane) gave compound 1f (2.96 g). 1H NMR (300 MHz, CDCl3): δ 7.91 (m, 1H), 7.53 (m, 1H), 4.28 (m, 1H), 4.22-4.11 (m, 2.5; H), 3.91 (m, 0.5; H), 3.83 (m, 1H), 3.73-3.60 (m, 3.5; H), 3.49 (m, 0.5; H), 3.41 (m, 1H), 2.11 (m, 1H), 1.89-1.73 (m, 1H), 1.44 (s, 9H). the resultant mixture was extracted with CH2Cl2 The organic layer was dried over Na2SO4 concentrated Purification by flash column chromatography (silica gel, 80% EtOAc/heptane)

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

Procedure: To a solution of compound 4d (TFA salt, 124 mg, 0.39 mmol) and compound 1e (94 mg, 0.55 mmol) in 1,2-DCE (2 mL) was added acetic acid (0.1 mL). To this mixture was added Na(OAc)3BH (132 mg, 0.624 mmol). The reaction was stirred at room temperature for 4 h. To the reaction mixture was added aq. NaHCO3, and the resultant mixture was extracted with CH2Cl2. The organic layer was dried over Na2SO4 and concentrated. Purification by flash column chromatography (silica gel, 5% MeOH/EtOAc+0.5% TEA) gave compound 4e (0.11 g). MS m/z (M+H+) 360.5. the resultant mixture was extracted with CH2Cl2 The organic layer was dried over Na2SO4 concentrated Purification by flash column chromatography (silica gel, 5% MeOH/EtOAc+0.5% TEA)

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

Procedure: To a solution of compound 1d (diHCl salt, 2.7 g, 10 mmol) and N-Boc azetidinone 1e (2.4 g, 14 mmol) in 1,2-DCE (50 mL) was added slowly Et3N (20 mmol) followed by acetic acid (3.5 mL). To this mixture was added Na(OAc)3BH (3.39 g, 16 mmol). The reaction was stirred at room temperature for 5 h. To the reaction mixture was added aq. NaHCO3, and the resultant mixture was extracted with CH2Cl2. The organic layer was dried over Na2SO4 and concentrated. Purification by flash column chromatography (silica gel, 80% EtOAc/heptane) gave compound 1f (2.96 g). 1H NMR (300 MHz, CDCl3): δ 7.91 (m, 1H), 7.53 (m, 1H), 4.28 (m, 1H), 4.22-4.11 (m, 2.5; H), 3.91 (m, 0.5; H), 3.83 (m, 1H), 3.73-3.60 (m, 3.5; H), 3.49 (m, 0.5; H), 3.41 (m, 1H), 2.11 (m, 1H), 1.89-1.73 (m, 1H), 1.44 (s, 9H). the resultant mixture was extracted with CH2Cl2 The organic layer was dried over Na2SO4 concentrated Purification by flash column chromatography (silica gel, 80% EtOAc/heptane)

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

Procedure: To a solution of compound 1d (diHCl salt, 2.7 g, 10 mmol) and N-Boc azetidinone 1e (2.4 g, 14 mmol) in 1,2-DCE (50 mL) was added slowly Et3N (20 mmol) followed by acetic acid (3.5 mL). To this mixture was added Na(OAc)3BH (3.39 g, 16 mmol). The reaction was stirred at room temperature for 5 h. To the reaction mixture was added aq. NaHCO3, and the resultant mixture was extracted with CH2Cl2. The organic layer was dried over Na2SO4 and concentrated. Purification by flash column chromatography (silica gel, 80% EtOAc/heptane) gave compound 1f (2.96 g). 1H NMR (300 MHz, CDCl3): δ 7.91 (m, 1H), 7.53 (m, 1H), 4.28 (m, 1H), 4.22-4.11 (m, 2.5; H), 3.91 (m, 0.5; H), 3.83 (m, 1H), 3.73-3.60 (m, 3.5; H), 3.49 (m, 0.5; H), 3.41 (m, 1H), 2.11 (m, 1H), 1.89-1.73 (m, 1H), 1.44 (s, 9H). the resultant mixture was extracted with CH2Cl2 The organic layer was dried over Na2SO4 concentrated Purification by flash column chromatography (silica gel, 80% EtOAc/heptane)

Conditions: temp:65.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Cerium chloride (71.4 g, 290 mmoles) was slurried in tetrahydrofuran (600 mL) and heated to 65° C. for 2.5 hours, then cooled to room temperature In a separate flask, 4-bromobenzaldehyde diethylacetal (100 g, 386 mmoles) was dissolved in tetrahydrofuran (750 mL). Magnesium turnings (5.9 g, 241 mmoles) and dibromoethane (0.5 mL) were added and the mixture heated to reflux for 2.5 hours, until all the magnesium had reacted. Heating was removed and the Grignard solution cooled in an ice bath. The cerium chloride/tetrahydrofuran slurry was cooled in an ice bath to 0° C. The Grignard solution was added, portionwise, and the mixture stirred at 0° C. for 45 minutes. N-(t-butoxycarbonyl)azetidinone (41.3 g, 241 mmoles) dissolved in tetrahydrofuran (200 mL) was added portionwise and the reaction allowed to stir at 0° C. for 30 minutes. The reaction was quenched with saturated sodium carbonate solution (500 mL) and then diluted with ethyl acetate (2000 mL). The organic phase was washed with water (3×500 mL), separated, dried over anhydrous magnesium sulphate, filtered and evaporated to dryness to give a yellow oil weighing 120 g which was purified using normal phase chromatography (600 g SiO2 column, loaded as a solution in 25 mL of dichloromethane, linear gradient of 10% tert-butylmethylether in n-heptane to 100% tert-butylmethylether over 60 minutes, 150 mL/minutes, 55 mL fractions using the ‘Threshold OR Slope’ method) to give a light yellow oil weighing 65 g, which NMR suggests is the desired acetal product. 1HNMR (CDCl3) δ ppm: 7.50 (4H), 5.50 (1H), 4.15 (2H), 4.30 (2H), 3.55 (4H), 1.50 (9H), 1.25 (6H); m/z (ESI) 252 [M+H-Boc]+. cooled to room temperature In a separate flask the mixture heated had reacted Heating was removed the Grignard solution cooled in an ice bath The cerium chloride/tetrahydrofuran slurry was cooled in an ice bath to 0° C The Grignard solution was added was added portionwise to stir at 0° C. for 30 minutes The reaction was quenched with saturated sodium carbonate solution (500 mL) diluted with ethyl acetate (2000 mL) The organic phase was washed with water (3×500 mL) separated dried over anhydrous magnesium sulphate filtered evaporated to dryness to give a yellow oil was purified linear gradient of 10% tert-butylmethylether in n-heptane to 100% tert-butylmethylether over 60 minutes to give a light yellow oil

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

Procedure: To a solution of compound 4d (TFA salt, 124 mg, 0.39 mmol) and compound 1e (94 mg, 0.55 mmol) in 1,2-DCE (2 mL) was added acetic acid (0.1 mL). To this mixture was added Na(OAc)3BH (132 mg, 0.624 mmol). The reaction was stirred at room temperature for 4 h. To the reaction mixture was added aq. NaHCO3, and the resultant mixture was extracted with CH2Cl2. The organic layer was dried over Na2SO4 and concentrated. Purification by flash column chromatography (silica gel, 5% MeOH/EtOAc+0.5% TEA) gave compound 4e (0.11 g). MS m/z (M+H+) 360.5. the resultant mixture was extracted with CH2Cl2 The organic layer was dried over Na2SO4 concentrated Purification by flash column chromatography (silica gel, 5% MeOH/EtOAc+0.5% TEA)

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

Procedure: To a solution of compound 1d (diHCl salt, 2.7 g, 10 mmol) and N-Boc azetidinone 1e (2.4 g, 14 mmol) in 1,2-DCE (50 mL) was added slowly Et3N (20 mmol) followed by acetic acid (3.5 mL). To this mixture was added Na(OAc)3BH (3.39 g, 16 mmol). The reaction was stirred at room temperature for 5 h. To the reaction mixture was added aq. NaHCO3, and the resultant mixture was extracted with CH2Cl2. The organic layer was dried over Na2SO4 and concentrated. Purification by flash column chromatography (silica gel, 80% EtOAc/heptane) gave compound 1f (2.96 g). 1H NMR (300 MHz, CDCl3): δ 7.91 (m, 1H), 7.53 (m, 1H), 4.28 (m, 1H), 4.22-4.11 (m, 2.5H), 3.91 (m, 0.5H), 3.83 (m, 1H), 3.73-3.60 (m, 3.5H), 3.49 (m, 0.5H), 3.41 (m, 1H), 2.11 (m, 1H), 1.89-1.73 (m, 1H), 1.44 (s, 9H). the resultant mixture was extracted with CH2Cl2 The organic layer was dried over Na2SO4 concentrated Purification by flash column chromatography (silica gel, 80% EtOAc/heptane)

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

Procedure: To a solution of compound 4d (TFA salt, 124 mg, 0.39 mmol) and compound 1e (94 mg, 0.55 mmol) in 1,2-DCE (2 mL) was added acetic acid (0.1 mL). To this mixture was added Na(OAc)3BH (132 mg, 0.624 mmol). The reaction was stirred at room temperature for 4 h. To the reaction mixture was added aq. NaHCO3, and the resultant mixture was extracted with CH2Cl2. The organic layer was dried over Na2SO4 and concentrated. Purification by flash column chromatography (silica gel, 5% MeOH/EtOAc+0.5% TEA) gave compound 4e (0.11 g). MS m/z (M+H+) 360.5. the resultant mixture was extracted with CH2Cl2 The organic layer was dried over Na2SO4 concentrated Purification by flash column chromatography (silica gel, 5% MeOH/EtOAc+0.5% TEA)

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

Procedure: To a solution of compound 1d (diHCl salt, 2.7 g, 10 mmol) and N-Boc azetidinone 1e (2.4 g, 14 mmol) in 1,2-DCE (50 mL) was added slowly Et3N (20 mmol) followed by acetic acid (3.5 mL). To this mixture was added Na(OAc)3BH (3.39 g, 16 mmol). The reaction was stirred at room temperature for 5 h. To the reaction mixture was added aq. NaHCO3, and the resultant mixture was extracted with CH2Cl2. The organic layer was dried over Na2SO4 and concentrated. Purification by flash column chromatography (silica gel, 80% EtOAc/heptane) gave compound 1f (2.96 g). 1H NMR (300 MHz, CDCl3): δ 7.91 (m, 1H), 7.53 (m, 1H), 4.28 (m, 1H), 4.22-4.11 (m, 2.5; H), 3.91 (m, 0.5; H), 3.83 (m, 1H), 3.73-3.60 (m, 3.5; H), 3.49 (m, 0.5; H), 3.41 (m, 1H), 2.11 (m, 1H), 1.89-1.73 (m, 1H), 1.44 (s, 9H). the resultant mixture was extracted with CH2Cl2 The organic layer was dried over Na2SO4 concentrated Purification by flash column chromatography (silica gel, 80% EtOAc/heptane)