Hydrofluoric Acid → (S)-4,4,6-Trifluoro-1-isopropyl-3,4-dihydronaphthalen-2(1H)-one

Participants

Reaction Conditions

Reaction Steps

1,1,7-Trifluoro-1,2,3,4-tetrahydronaphthalene (52): A solution of N-iodosuccinimide (32.3 g, 144.0 mmol) in dichloromethane (260 mL) was cooled to −78° C. in a plastic round bottom flask. A 70% solution of hydrogen fluoride in pyridine (18 mL) followed by a dichloromethane solution (20 mL) of dithiolane 61 (8.65 g, 36.0 mmol) were added dropwise. Upon completion of addition the reaction was warmed to −50° C. and stirred at this temperature for 3 h. The reaction was then poured into ice cold saturated sodium bicarbonate (200 mL) followed by a saturated solution of sodium thiosulfate (150 mL). The colored reaction became colorless and biphasic. The organic phase was separated, dried (sodium sulfate) and concentrated to give a yellow oil. The product was purified by silica gel chromatography with a gradient heptanes/ethyl acetate eluent system on an ISCO companion system to give the desired product as a yellow oil (3.11 g, 16.7 mmol, 46% yield). 1H NMR (400 MHz, CDCl3) δ: 7.34 (d, J=8 Hz, 1H), 7.07 (m, 1H), 7.05 (m, 1H), 2.80 (brs, 2H), 2.26 (m, 2H), 1.99 (m, 2H); 19F NMR (400 MHz, CDCl3) δ: −91.7 (s, 2H), −122.8 (s, 1H).

Provenance & Evidence