Pentafluorophenyl Trifluoroacetate → 3-[(tert-Butyl)oxycarbonyl]propyl 2,3,4,5,6-pentafluorophenyl butane-1,4-dioate

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Reaction Steps

Compound 3 (2.0 g, 5.7 mmol) was hydrogenated for 20 h at 40 psi in THF (100 mL) in the presence of 0.2 g of 10% Pd/C. The catalyst was removed by filtration through Celite and filtrate concentrated. The acid was dissolved in 20 mL of anhydrous CH2Cl2. Diisopropylethylamine ((0.88 g, 6.8 mmol) was added followed by pentafluorophenyl trifluoroacetate (1.9 g, 6.8 mmol). After being kept at room temperature for 1 h solvent was evaporated and residue chromatographed on silica (ethyl acetate-hexane) to afford 2.2 g (91%) of 4 as viscous liquid. 1H NMR (DMSO-d6) δ 4.05 (t, J=6 Hz, 2H), 3.04 (t, J=6 Hz, 2H), 2.72 (t, J=6 Hz, 2H), 2.26 (t, J=7 Hz, 2H), 1.78 (q, 2H), 1.38 (s, 9H).

Provenance & Evidence