tert-butyl N-[(2R)-3-oxobutan-2-yl]carbamate

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

Procedure: In a round-bottomed flask, [(R)-1-(methoxy-methyl-carbamoyl)-ethyl]-carbamic acid tert-butyl ester (3.00 g, 12.9 mmol) was dissolved in THF (100 ml). The solution was cooled to −16° C. (NaCl/ice bath) and methylmagnesium bromide (3.0 M in diethyl ether, 12.0 ml, 36.0 mmol) was added dropwise over 20 min. After the addition, the reaction mixture was allowed to warm slowly to room temperature overnight. The reaction mixture was cooled to 0° C., quenched with saturated aqueous NH4Cl and extracted with EtOAc (2×). The combined organic layers were washed with water and brine then dried over sodium sulfate, filtered and concentrated. The residue was chromatographed over silica gel with EtOAc/hexanes (gradient 0-20% EtOAc) to afford 2.21 g (91%) of ((R)-1-methyl-2-oxo-propyl)-carbamic acid tert-butyl ester as a white solid. was added dropwise over 20 min After the addition The reaction mixture was cooled to 0° C. quenched with saturated aqueous NH4Cl extracted with EtOAc (2×) The combined organic layers were washed with water and brine then dried over sodium sulfate filtered concentrated The residue was chromatographed over silica gel with EtOAc/hexanes (gradient 0-20% EtOAc)

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

Procedure: In a round-bottomed flask, [(R)-1-(methoxy-methyl-carbamoyl)-ethyl]-carbamic acid tert-butyl ester (3.00 g, 12.9 mmol) was dissolved in THF (100 ml). The solution was cooled to −16° C. (NaCl/ice bath) and methylmagnesium bromide (3.0 M in diethyl ether, 12.0 ml, 36.0 mmol) was added dropwise over 20 min. After the addition, the reaction mixture was allowed to warm slowly to room temperature overnight. The reaction mixture was cooled to 0° C., quenched with saturated aqueous NH4Cl and extracted with EtOAc (2×). The combined organic layers were washed with water and brine then dried over sodium sulfate, filtered and concentrated. The residue was chromatographed over silica gel with EtOAc/hexanes (gradient 0-20% EtOAc) to afford 2.21 g (91%) of ((R)-1-methyl-2-oxo-propyl)-carbamic acid tert-butyl ester as a white solid. was added dropwise over 20 min After the addition The reaction mixture was cooled to 0° C. quenched with saturated aqueous NH4Cl extracted with EtOAc (2×) The combined organic layers were washed with water and brine then dried over sodium sulfate filtered concentrated The residue was chromatographed over silica gel with EtOAc/hexanes (gradient 0-20% EtOAc)

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

Procedure: In a round-bottomed flask, [(R)-1-(methoxy-methyl-carbamoyl)-ethyl]-carbamic acid tert-butyl ester (3.00 g, 12.9 mmol) was dissolved in THF (100 ml). The solution was cooled to −16° C. (NaCl/ice bath) and methylmagnesium bromide (3.0 M in diethyl ether, 12.0 ml, 36.0 mmol) was added dropwise over 20 min. After the addition, the reaction mixture was allowed to warm slowly to room temperature overnight. The reaction mixture was cooled to 0° C., quenched with saturated aqueous NH4Cl and extracted with EtOAc (2×). The combined organic layers were washed with water and brine then dried over sodium sulfate, filtered and concentrated. The residue was chromatographed over silica gel with EtOAc/hexanes (gradient 0-20% EtOAc) to afford 2.21 g (91%) of ((R)-1-methyl-2-oxo-propyl)-carbamic acid tert-butyl ester as a white solid. was added dropwise over 20 min After the addition The reaction mixture was cooled to 0° C. quenched with saturated aqueous NH4Cl extracted with EtOAc (2×) The combined organic layers were washed with water and brine then dried over sodium sulfate filtered concentrated The residue was chromatographed over silica gel with EtOAc/hexanes (gradient 0-20% EtOAc)

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

Procedure: In a round-bottomed flask, [(R)-1-(methoxy-methyl-carbamoyl)-ethyl]-carbamic acid tert-butyl ester (3.00 g, 12.9 mmol) was dissolved in THF (100 ml). The solution was cooled to −16° C. (NaCl/ice bath) and methylmagnesium bromide (3.0 M in diethyl ether, 12.0 ml, 36.0 mmol) was added dropwise over 20 min. After the addition, the reaction mixture was allowed to warm slowly to room temperature overnight. The reaction mixture was cooled to 0° C., quenched with saturated aqueous NH4Cl and extracted with EtOAc (2×). The combined organic layers were washed with water and brine then dried over sodium sulfate, filtered and concentrated. The residue was chromatographed over silica gel with EtOAc/hexanes (gradient 0-20% EtOAc) to afford 2.21 g (91%) of ((R)-1-methyl-2-oxo-propyl)-carbamic acid tert-butyl ester as a white solid. was added dropwise over 20 min After the addition The reaction mixture was cooled to 0° C. quenched with saturated aqueous NH4Cl extracted with EtOAc (2×) The combined organic layers were washed with water and brine then dried over sodium sulfate filtered concentrated The residue was chromatographed over silica gel with EtOAc/hexanes (gradient 0-20% EtOAc)