methyl (2R)-3-chloro-2-[(2-methylpropan-2-yl)oxycarbonylamino]propanoate

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

Procedure: A solution of methyl N-(tert-butoxycarbonyl)-3-chloro-L-alaninate (56, 2.13 g, 9.0 mmol) in ethanol (41 ml) stirred at 0° C. under N2 atmosphere was treated with a 2M solution of LiBH4 in THF (5 mL, 10 mmol) (slow addition). The reaction mixture was slowly warmed up to room temperature and further stirred for 4 h, cooled to 0° C., treated with saturated NaHCO3 (5 mL) followed by acetone (5 mL), stirred for 10 minutes, diluted with DCM and washed with brine, dried over MgSO4 filtered and concentrated to afford 1.94 (100% yield) of title compound as a white solid. MS: m/z=232.0 (MNa+). cooled to 0° C. stirred for 10 minutes washed with brine dried over MgSO4 filtered concentrated

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

Procedure: A solution of methyl N-(tert-butoxycarbonyl)-3-chloro-L-alaninate (56, 2.13 g, 9.0 mmol) in ethanol (41 ml) stirred at 0° C. under N2 atmosphere was treated with a 2M solution of LiBH4 in THF (5 mL, 10 mmol) (slow addition). The reaction mixture was slowly warmed up to room temperature and further stirred for 4 h, cooled to 0° C., treated with saturated NaHCO3 (5 mL) followed by acetone (5 mL), stirred for 10 minutes, diluted with DCM and washed with brine, dried over MgSO4 filtered and concentrated to afford 1.94 (100% yield) of title compound as a white solid. MS: m/z=232.0 (MNa+). cooled to 0° C. stirred for 10 minutes washed with brine dried over MgSO4 filtered concentrated

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

Procedure: A solution of triphenylphosphine (4.55 g, 17.4 mmol) and hexachloroethane (3.9 g, 16.5 mmol) in 1,2-dichloroethane (18 mL) prepared at 0° C. was added via cannula into a flask containing a solution of methyl N-(tert-butoxycarbonyl)-L-serinate (3.2 g, 14.6 mmol) in 1,2-dichloroethane DCE (40 mL), kept at 0° C. under N2 atmosphere. After the addition was completed, the reaction mixture was further stirred at room temperature for 2 h, diluted with DCM, washed with sat NaHCO3, dried over MgSO4, filtered and concentrated. Purification made through chromatographic column of silicagel eluted with 10% to 50% EtOAc in hexane for 30 min, to afford 2.13 g (61% yield) of title compound as white crystals. MS: m/z=260.0 (MNa+). was added via cannula into a flask kept at 0° C. under N2 atmosphere After the addition washed dried over MgSO4 filtered concentrated Purification of silicagel eluted with 10% to 50% EtOAc in hexane for 30 min

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

Procedure: A solution of methyl N-(tert-butoxycarbonyl)-3-chloro-L-alaninate (56, 2.13 g, 9.0 mmol) in ethanol (41 ml) stirred at 0° C. under N2 atmosphere was treated with a 2M solution of LiBH4 in THF (5 mL, 10 mmol) (slow addition). The reaction mixture was slowly warmed up to room temperature and further stirred for 4 h, cooled to 0° C., treated with saturated NaHCO3 (5 mL) followed by acetone (5 mL), stirred for 10 minutes, diluted with DCM and washed with brine, dried over MgSO4 filtered and concentrated to afford 1.94 (100% yield) of title compound as a white solid. MS: m/z=232.0 (MNa+). cooled to 0° C. stirred for 10 minutes washed with brine dried over MgSO4 filtered concentrated

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

Procedure: A solution of triphenylphosphine (4.55 g, 17.4 mmol) and hexachloroethane (3.9 g, 16.5 mmol) in 1,2-dichloroethane (18 mL) prepared at 0° C. was added via cannula into a flask containing a solution of methyl N-(tert-butoxycarbonyl)-L-serinate (3.2 g, 14.6 mmol) in 1,2-dichloroethane DCE (40 mL), kept at 0° C. under N2 atmosphere. After the addition was completed, the reaction mixture was further stirred at room temperature for 2 h, diluted with DCM, washed with sat NaHCO3, dried over MgSO4, filtered and concentrated. Purification made through chromatographic column of silicagel eluted with 10% to 50% EtOAc in hexane for 30 min, to afford 2.13 g (61% yield) of title compound as white crystals. MS: m/z=260.0 (MNa+). was added via cannula into a flask kept at 0° C. under N2 atmosphere After the addition washed dried over MgSO4 filtered concentrated Purification of silicagel eluted with 10% to 50% EtOAc in hexane for 30 min