2,3,5,6-Tetrafluorophenol → (S)-3-Benzyloxycarbonylamino-4-oxo-5-(2,3,5,6-tetrafluoro-phenoxy)-pentanoic Acid Tert-Butyl Ester

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Reaction Steps

Potassium fluoride (2.8 g) was added portionwise to a stirred solution of (S)-3-benzyloxycarbonylamino-5-bromo-4-oxo-pentanoic acid tert-butyl ester (18.6 g) and 2,3,5,6-tetrafluorophenol (9.3 g) in anhydrous DMF (250 mL) under nitrogen at room temperature. The mixture was then stirred for 18 hours before being quenched with ethyl acetate and water. The organic layer was removed and washed with sodium bicarbonate solution, dried (magnesium sulfate) and concentrated to give the sub-title product as an off-white solid (21.1 g, 96%). 1H NMR (400 MHz, CDCl3) δ 1.43 (9H, s), 2.76 (1H, dd), 3.06 (1H, dd), 4.67-4.71 (1H, m), 5.12 (1 h, d), 5.22 (1H, d), 5.86 (1H, d), 7.35-7.38 (5H, m) ppm; 19F NMR (376 MHz, CDCl3) (proton decoupled) δ −139.98, −140.00, −140.04, −140.06, −157.05, −157.07, −157.11, −157.13; MS ES (+) 486.23 (M+H).

Provenance & Evidence