methyl (4S)-2-oxo-1,3-oxazolidine-4-carboxylate

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

Procedure: To (S)-serine methyl ester hydrochloride (20 g, 128.64 mmol) in water (230 ml) was added KHCO3 (14.16 g, 141.52 mmol) and K2CO3 (19.56 g, 141.52 mmol) at room temperature. It was then cooled by an ice bath and triphosgene (19.04 gm, 64.32 mmol) was added in toluene (192 ml) via an addition funnel over 25 minutes. The reaction mixture turned cloudy. After 2 h, reaction phases were separated and the aqueous layer was lyophilized to yield (S)-4-carbomethoxy-2-oxazolidinone as a white solid (16.5 g) in 88% yield. It was then cooled by an ice bath reaction phases were separated

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

Procedure: To (S)-serine methyl ester hydrochloride (20 g, 128.64 mmol) in water (230 ml) was added KHCO3 (14.16 g, 141.52 mmol) and K2CO3 (19.56 g, 141.52 mmol) at room temperature. It was then cooled by an ice bath and triphosgene (19.04 gm, 64.32 mmol) was added in toluene (192 ml) via an addition funnel over 25 minutes. The reaction mixture turned cloudy. After 2 h, reaction phases were separated and the aqueous layer was lyophilized to yield (S)-4-carbomethoxy-2-oxazolidinone as a white solid (16.5 g) in 88% yield. It was then cooled by an ice bath reaction phases were separated

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

Procedure: A solution of L-serine methyl ester hydrochloride (3.063 kg) in dichloromethane (24.1 L) at 0° C. was treated with triethylamine (5.908 kg), stirred for 30 minutes, treated with triphosgene (1.949 kg) in dichloromethane (5.356 kg) over 6.5 hours, stirred for 45 minutes, treated with hexanes (12.23 kg), stirred for 55 minutes, and filtered with ethyl acetate (16.013 kg). The filtrate was concentrated to provide a 35% (w/w) solution of the desired product (93.5%, 98% ee) in ethyl acetate. 1H NMR (300 MHz, CDCl3) δ6.55 (br s, 1H), 4.62 (dd, J=9, 9 Hz, 1H), 4.53 (dd, J=4, 9 Hz, 1H), 4.45 (dd, J=4, 9 Hz, 1H), 3.83 (s, 3H). stirred for 45 minutes stirred for 55 minutes filtered with ethyl acetate (16.013 kg) The filtrate was concentrated

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

Procedure: To (S)-serine methyl ester hydrochloride (20 g, 128.64 mmol) in water (230 ml) was added KHCO3 (14.16 g, 141.52 mmol) and K2CO3 (19.56 g, 141.52 mmol) at room temperature. It was then cooled by an ice bath and triphosgene (19.04 gm, 64.32 mmol) was added in toluene (192 ml) via an addition funnel over 25 minutes. The reaction mixture turned cloudy. After 2 h, reaction phases were separated and the aqueous layer was lyophilized to yield (S)-4-carbomethoxy-2-oxazolidinone as a white solid (16.5 g) in 88% yield. It was then cooled by an ice bath reaction phases were separated

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

Procedure: To (S)-serine methyl ester hydrochloride (20 g, 128.64 mmol) in water (230 ml) was added KHCO3 (14.16 g, 141.52 mmol) and K2CO3 (19.56 g, 141.52 mmol) at room temperature. It was then cooled by an ice bath and triphosgene (19.04 gm, 64.32 mmol) was added in toluene (192 ml) via an addition funnel over 25 minutes. The reaction mixture turned cloudy. After 2 h, reaction phases were separated and the aqueous layer was lyophilized to yield (S)-4-carbomethoxy-2-oxazolidinone as a white solid (16.5 g) in 88% yield. It was then cooled by an ice bath reaction phases were separated