methyl (2R)-3-hydroxy-2-(phenylmethoxycarbonylamino)propanoate

Conditions: temp:22.51; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 130 L of methylene chloride was added; 20.5 g of (R)-methyl 2-(benzyloxycarbonylamino)-3-hydroxypropanate to a reactor; then stirred for 30 minutes; and then 0.4 kg of sulfuric acid was added. Isobutylene gas was bubbled for 24 hours while its temperature was maintained at 20-25° C. After completing the reaction, 18 L of saturated sodium hydrogen carbonate aqueous solution was slowly added, stirred for 1 hour, and then an organic layer was isolated. 5 kg of sodium sulfate was added to the organic layer, stirred for 1 hour, filtered, washed, and then the filtrate was concentrated under reduced pressure to obtain 29.3 kg of a title compound. Isobutylene gas was bubbled for 24 hours while its temperature the reaction, 18 L of saturated sodium hydrogen carbonate aqueous solution was slowly added stirred for 1 hour an organic layer was isolated stirred for 1 hour filtered washed the filtrate was concentrated under reduced pressure

Conditions: temp:60.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of methyl N-[(benzyloxy)carbonyl]-D-serinate (1013 mg) and 2,2-dimethoxypropane (4166 mg) in acetone (20 mL) was added pyridin-1-ium 4-methylbenzenesulfonate (201 mg) at room temperature, and the reaction mixture was stirred at 60° C. overnight. The solvent was evaporated, and the residue was purified by silica gel column chromatography (ethyl acetate/hexane) to give the title compound (860 mg). The solvent was evaporated the residue was purified by silica gel column chromatography (ethyl acetate/hexane)

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

Procedure: To a solution of D-serine (10.5 g) in methanol (100 mL) was added thionyl chloride (8.76 mL) under ice-cooling. The reaction mixture was stirred at room temperature for 4 hr, and to the reaction mixture were added sodium hydrogen carbonate (25.2 g) and benzyl chloroformate (17.1 mL). The reaction mixture was stirred at room temperature overnight, the reaction mixture was added to water, and the mixture was extracted with ethyl acetate. The organic layer was separated, washed with saturated brine, dried over magnesium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (ethyl acetate/hexane) to give the title compound (10.3 g). cooling The reaction mixture was stirred at room temperature overnight the mixture was extracted with ethyl acetate The organic layer was separated washed with saturated brine dried over magnesium sulfate concentrated under reduced pressure The residue was purified by silica gel column chromatography (ethyl acetate/hexane)