3-[3-(Trifluoromethoxy)phenyl]propanoic acid → 5-(Trifluoromethoxy)-2,3-dihydro-1H-inden-1-one

Participants

Reaction Conditions

Reaction Steps

158e (9.0 g, 38.5 mmol) was added portionwise to chlorosulfonic acid (100 mL) while cooling with an iced bath. See FIG. 4. The resulting mixture was stirred at 0° C. for 1.5 h, poured into ice-water (1 L), and extracted with EtOAc (200 mL×3). The organic layers were dried over anhydrous sodium sulfate and concentrated. The residue was purified with by column chromatography on silica gel (ethyl acetate:petroleum ether=1:3) to afford 5-(trifluoromethoxy)-2,3-dihydro-1H-inden-1-one 158f (800 mg, 9.6%) as a yellow solid. 1H NMR (400 MHz, CDCl3): δ 7.72 (d, J=8.4 Hz, 1H), 7.24 (s, 1H), 7.14 (d, J=8.4 Hz, 1H), 3.11 (t, J=5.6 Hz, 2H), 2.69-2.66 (m, 2H).

Provenance & Evidence