Sodium Carbonate → chloromethyl (2S)-2-(((tert-butoxy)carbonyl)amino)-3-methylbutanoate

Participants

Reaction Steps

To a vigorously stirred mixture of (S)-2-((tert-butoxycarbonyl)amino)-3-methylbutanoic acid (4 g, 18.41 mmol), tetrabutylammonium hydrogen sulfate (1.25 g, 3.68 mmol), and Na2CO3 (9.76 g, 92 mmol) in DCM 80 (mL) and water (80 mL), cooled in an ice/water bath, was slowly added chloromethyl chlorosulfate (3.8 mL, 36.8 mmol) over 4 min. After stirring in the ice/water bath for 30 min, the cold bath was removed and the reaction mixture was allowed to stir at room temperature. After stirring 16 h at room temperature, the reaction mixture was diluted with water and extracted with DCM. The aqueous layer was back extracted with DCM and the combined organic layers were dried over MgSO4, filtered and concentrated to afford Intermediate 38A (5.45 g).

Provenance & Evidence