Proton sponge → HCID 67145355, compound

Participants

Reaction Steps

Trimethyloxonium tetrafluoroborate (2.3 g, 16 mmol) was taken up in 10 mL of CH2Cl2. Proton sponge (3.3 g, 16 mmol) and (2S,3S)-2-(tert-butoxycarbonyl)-4-hydroxy-3-(4-(trifluoromethyl)phenyl)butyl pivalate (2.25 g, 5.2 mmol) were added to the mixture in 15 mL of CH2Cl2. The mixture was shielded from light and stirred for 3 hours. The mixture was carefully quenched with 70 mL of 10% aq HCl and extracted three times with 100 mL of CH2Cl2. The combined organic extracts were dried over MgSO4. Filtration and concentration under reduced pressure, followed by flash chromatography on silica gel (5% to 25% EtOAc/hexanes) afforded (2S,3S)-2-(tert-butoxycarbonyl)-4-methoxy-3-(4-(trifluoromethyl)phenyl)butyl pivalate (1.4 g, 60% yield) as a white solid. 1H NMR (400 MHz, CDCl3) δ ppm 7.58 (d, J=8.02 Hz, 2H) 7.34 (d, J=8.02 Hz, 2H) 4.42-4.32 (m, 2H) 4.15-4.00 (m, 2H) 3.73-3.63 (m, 2H) 3.34 (s, 3H) 1.35 (s, 9H) 1.19 (s, 9H).

Provenance & Evidence