Pyridine → (S)-Methyl 2-((tert-butoxycarbonyl)amino)-3-(4-(((trifluoromethyl)sulfonyl)oxy)phenyl)propanoate

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Reaction Steps

Trifluoromethanesulfonic anhydride (3.27 ml, 19.47 mmol) was slowly added to a solution of Boc-L-tyrosine methyl ester (5.0 g, 16.93 mmol) and pyridine (4.11 ml, 50.79 mmol) in dichloromethane (145 ml) at 0° C. and the resulting orange solution was stirred at room temperature for 4 h. The reaction was quenched by addition of NaHCO3 solution (150 ml) and the organic layer was separated, washed with saturated aqueous NaHCO3 (2×100 ml) and brine (1×100 ml), and dried (MgSO4). The solvent was concentrated under reduced pressure to yield (S)-2-tert-butoxycarbonylamino-3-(4-trifluoromethanesulfonyloxyphenyl) propionic acid methyl ester (6.52 g, 90%) that was used in the next step without further purification.

Provenance & Evidence