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

Participants

Reaction Steps

Triflic anhydride (5.05 ml, 30 mmol) was added to a mixture of N-BOC tyrosine methyl ester (7.38 g, 25 mmol) and pyridine (10 ml, 125 mmol) in DCM (40 ml) at 0°. After 45 min at 0° water (80 ml) and DCM (100 ml) were added. The organic phase was washed with NaOH aq. (0.5 M, 60 ml), water (60 ml), citric acid (10%, 2×80 ml) and water (60 ml), dried (Na2SO4) and concentrated in vacuo to give the title compound as a yellow oil which solidified on standing (10.6 g). δH (CDCl3) 7.26-7.18 (4H, m), 5.05 (1H, v br d), 4.59 (1H, v br q), 3.70 (3H, s), 3.16 (1H, dd, J 13.7, 5.7 Hz), 3.02 (1H, dd, J 13.8, 6.5 Hz), 1.40 (9H, s); m/z (ES+, 70 V) 450 (M++Na).

Provenance & Evidence