4-Toluenesulfonyl chloride → toluene-4-sulfonic acid (S)-2-tert-butoxycarbonylamino-4,4-dimethyl-pentyl ester

Participants

Reaction Steps

To a stirred solution of ((S)-1-hydroxymethyl-3,3-dimethyl-butyl)-carbamic acid tert-butyl ester (3.0 g, 13.0 mmol, 1.0 equiv.) in dry pyridine (14.8 mL) was added tosyl chloride (3.7 g, 19.4 mmol, 1.5 equiv) portionwise at 0° C. under nitrogen. After 4 hours of stirring at room temperature, the reaction mixture was extracted with ethyl acetate (200 mL), washed with water (3×200 mL) followed by brine (2×100 mL), and dried over anhydrous sodium sulfate to give a crude residue. The residue was purified by silica gel column chromatography (100-200 mesh) using a gradient of 5-10% ethyl acetate/hexanes to give toluene-4-sulfonic acid(S)-2-tert-butoxycarbonylamino-4,4-dimethyl-pentyl ester (3 g, 60%).

Provenance & Evidence