Hydrochloric Acid → 1-(Cyclopent-1-en-1-yl)-2,4-difluorobenzene

Participants

Reaction Steps

To a 0.497 M solution of (2,4-difluorophenyl)magnesium bromide (32.4 g, 149 mmol) in THF at 0° C. was carefully added cyclopentanone (13.23 mL, 149 mmol). Upon the end of the addition, the reaction mixture was heated at reflux for 2 h. Ice (10 g) and 6 N aqueous hydrochloric acid were added. The reaction mixture was extracted with ether. The combined organic extracts were washed with a saturated aqueous solution of sodium hydrogen sulfite, a saturated aqueous solution of sodium bicarbonate and water. The organic layer was dried over anhydrous magnesium sulfate and filtered. The solvent was removed in vacuo and the residue was purified by column chromatography on silica gel to give 1-cyclopentenyl-2,4-difluorobenzene (7.064 g, 39.2 mmol, 26.3% yield) as a colorless oil. LC-MS (M+H)+=181.0. 1H NMR (500 MHz, CDCl3) δ ppm 7.22-7.31 (1H, m), 6.75-6.85 (2H, m), 6.26-6.31 (1H, m), 2.68-2.74 (2H, m), 2.51-2.58 (2H, m), 1.93-2.02 (2H, m).

Provenance & Evidence