benzyl (2S,3R)-2-amino-3-hydroxybutanoate

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

Procedure: L-threonine 21.2 g (178 mmol) was dissolved in toluene (100 mL), and benzyl alcohol (100 mL, 966 mmol) and p-toluenesulfonic acid monohydrate (35.0 g, 194 mmol) were added, followed by heating to reflux for 17 hours under nitrogen atmosphere. After cooling to room temperature, water (200 mL) was added, followed by washing three times with ethyl acetate (100 mL). To the aqueous layer, a saturated aqueous sodium hydrogencarbonate solution was added, and extraction was carried out three times with ethyl acetate (100 mL). After the organic layer was washed with saturated brine, drying was carried out over anhydrous magnesium sulfate, and the resulting residue was purified using silica gel column chromatography (elution solvent: methanol/methylene chloride=0%-15%) to afford the desired product (10.6 g, yield 28%) as a white solid. by heating to reflux for 17 hours under nitrogen atmosphere by washing three times with ethyl acetate (100 mL) To the aqueous layer, a saturated aqueous sodium hydrogencarbonate solution was added extraction After the organic layer was washed with saturated brine drying the resulting residue was purified silica gel column chromatography (elution solvent: methanol/methylene chloride=0%-15%)

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

Procedure: L-threonine 21.2 g (178 mmol) was dissolved in toluene (100 mL), and benzyl alcohol (100 mL, 966 mmol) and p-toluenesulfonic acid monohydrate (35.0 g, 194 mmol) were added, followed by heating to reflux for 17 hours under nitrogen atmosphere. After cooling to room temperature, water (200 mL) was added, followed by washing three times with ethyl acetate (100 mL). To the aqueous layer, a saturated aqueous sodium hydrogencarbonate solution was added, and extraction was carried out three times with ethyl acetate (100 mL). After the organic layer was washed with saturated brine, drying was carried out over anhydrous magnesium sulfate, and the resulting residue was purified using silica gel column chromatography (elution solvent: methanol/methylene chloride=0%-15%) to afford the desired product (10.6 g, yield 28%) as a white solid. by heating to reflux for 17 hours under nitrogen atmosphere by washing three times with ethyl acetate (100 mL) To the aqueous layer, a saturated aqueous sodium hydrogencarbonate solution was added extraction After the organic layer was washed with saturated brine drying the resulting residue was purified silica gel column chromatography (elution solvent: methanol/methylene chloride=0%-15%)

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

Procedure: L-threonine 21.2 g (178 mmol) was dissolved in toluene (100 mL), and benzyl alcohol (100 mL, 966 mmol) and p-toluenesulfonic acid monohydrate (35.0 g, 194 mmol) were added, followed by heating to reflux for 17 hours under nitrogen atmosphere. After cooling to room temperature, water (200 mL) was added, followed by washing three times with ethyl acetate (100 mL). To the aqueous layer, a saturated aqueous sodium hydrogencarbonate solution was added, and extraction was carried out three times with ethyl acetate (100 mL). After the organic layer was washed with saturated brine, drying was carried out over anhydrous magnesium sulfate, and the resulting residue was purified using silica gel column chromatography (elution solvent: methanol/methylene chloride=0%-15%) to afford the desired product (10.6 g, yield 28%) as a white solid. by heating to reflux for 17 hours under nitrogen atmosphere by washing three times with ethyl acetate (100 mL) To the aqueous layer, a saturated aqueous sodium hydrogencarbonate solution was added extraction After the organic layer was washed with saturated brine drying the resulting residue was purified silica gel column chromatography (elution solvent: methanol/methylene chloride=0%-15%)

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

Procedure: L-threonine 21.2 g (178 mmol) was dissolved in toluene (100 mL), and benzyl alcohol (100 mL, 966 mmol) and p-toluenesulfonic acid monohydrate (35.0 g, 194 mmol) were added, followed by heating to reflux for 17 hours under nitrogen atmosphere. After cooling to room temperature, water (200 mL) was added, followed by washing three times with ethyl acetate (100 mL). To the aqueous layer, a saturated aqueous sodium hydrogencarbonate solution was added, and extraction was carried out three times with ethyl acetate (100 mL). After the organic layer was washed with saturated brine, drying was carried out over anhydrous magnesium sulfate, and the resulting residue was purified using silica gel column chromatography (elution solvent: methanol/methylene chloride=0%-15%) to afford the desired product (10.6 g, yield 28%) as a white solid. by heating to reflux for 17 hours under nitrogen atmosphere by washing three times with ethyl acetate (100 mL) To the aqueous layer, a saturated aqueous sodium hydrogencarbonate solution was added extraction After the organic layer was washed with saturated brine drying the resulting residue was purified silica gel column chromatography (elution solvent: methanol/methylene chloride=0%-15%)